UNIVERSITY OF HELSINKI
DEPARTMENT OF PHYSICS
REPORT SERIES IN GEOPHYSICS
No 60
B
1m
C
550 m
PHYSICAL PROPERTIES OF METEORITES
AND THEIR ROLE IN PLANETOLOGY
Tomáš Kohout
HELSINKI 2009
5 cm
UNIVERSITY OF HELSINKI
DEPARTMENT OF PHYSICS
REPORT SERIES IN GEOPHYSICS
No 60
PHYSICAL PROPERTIES OF METEORITES
AND THEIR ROLE IN PLANETOLOGY
Cover picture:
25143-Itokawa is a rubble-pile asteroid (A). Its longest dimension is 550 m. The
Muses sea area was the landing site (marked with white square) of the Hayabusa
space probe. The close-up image of the surface regolith (B) reveals that fragments
smaller than ~ 1 cm are missing due to the low gravity of Itokawa. The composition
of Itokawa is close to the Bjurböle meteorite (C) with its typical ~ mm sized
chondrules. Note the different appearance and texture of the compositionally identical
materials on various scales. Itokawa images are from Japanese Aerospace and
Exploration Agency (JAXA).
Tomáš Kohout
HELSINKI 2009
Supervisors:
Prof. Lauri J. Pesonen
Department of Physics
Division of Atmospheric Sciences
and Geophysics
University of Helsinki
Helsinki, Finland
Dr. Miroslav Kobr
Department of Applied Geophysics
Charles University in Prague
Prague, Czech Republic
Pre-examiners:
Doc. Ilmo Kukkonen
Geological Survey of Finland
Espoo, Finland
Dr. Eduard Petrovský
Institute of Geophysics
Academy of Sciences of the Czech Republic
Prague, Czech Republic
Opponent:
Custos:
Dr. Minoru Funaki
National Institute of Polar Research
Tokyo, Japan
Prof. Lauri J. Pesonen
Department of Physics
Division of Atmospheric Sciences
and Geophysics
University of Helsinki
Helsinki, Finland
Report Series in Geophysics No. 60
ISBN 978-952-10-5444-0 (paperback)
ISSN 0355-8630
Helsinki 2009
Yliopistopaino
ISBN 978-952-10-5445-7 (pdf)
http://ethesis.helsinki.fi
Helsinki 2009
Helsingin yliopiston verkkojulkaisut
PHYSICAL PROPERTIES OF METEORITES
AND THEIR ROLE IN PLANETOLOGY
Tomáš Kohout
ACADEMIC DISSERTATION IN GEOPHYSICS
To be presented, with the permission of the Faculty of Science of the University of Helsinki and the
Faculty of Science of the Charles University in Prague, for public criticism in the Auditorium E204
of Physicum, Gustaf Hällströmin katu 2A, on June 29th, 2009, at 12 o’clock noon.
Helsinki 2009
3
4
Table of contents
Preface
6
Abstract
7
1. Introduction to meteorites and their parent bodies – asteroids and planets
11
2. Physical properties of meteorites – measurements and applications
18
3. Meteorites in the “cold” interplanetary environment
25
4. Magnetic fields in the Solar System and paleofield estimates from meteorites
29
5. Testing the reliability of the meteorite paleomagnetic and paleointensity data
33
6. Testing the effect of low-pressure shock demagnetization on Avanhandava chondrules 35
7. Testing the origin of Neuschwanstein’s NRM
37
8. Efficiency of TRM acquisition in various materials
39
9. Conclusions
41
10. References
42
Appendix
51
Original articles
60
5
Preface
My doctoral studies and successful completion of this thesis would not have been possible
without the help of many colleagues and friends.
First of all, I would like to thank to my supervisors – Prof. Lauri J. Pesonen for inviting me to
Finland, for enabling my studies at the Division of Geophysics, University of Helsinki and
numerous constructive suggestions and advice, and Dr. Miroslav Kobr for enabling my studies at
the Department of Applied Geophysics, Charles University in Prague, for his support and numerous
constructive suggestions and advice.
Secondly, I would like to thank the pre-reviewers of this thesis – Dr. Ilmo Kukkonen and Dr.
Eduard Petrovský for critical, constructive comments and suggestions to the manuscript.
I would also like to thank all my colleagues, namely Dr. Mario Acuna, Dr. Addi Bischoff, MSc.
Michal Bucko, Mr. Alan Campbell, Mr. Aurélien Cheron, Dr. Alexander Deutsch, Dr. Fabio
Donadini, MSc. Tiiu Elbra, Dr. Minoru Funaki, MSc. Jakub Haloda, Dr. Michael Jackson, Dr.
Gunther Kletetschka, Dr. Vladimír Kohout, Dr. Andrei Kosterov, Ms. Ulpu Leijala, Prof. Martti
Lehtinen, MSc. Ioanna Merkouriadi, Dr. Petr Pruner, Dr. Johanna Salminen, MSc. Selen Raiskila,
MSc. Kai Rasmus, MSc. Petr Schnabl, MSc. Stanislav Šlechta, M.Sc. Patricie Týcová, Dr. Peter J.
Wasilewski and Dr. Jutta Zipfel for their help, advise and support, to all co-authors of the original
articles for their contribution, to the staff of the meteorite collections and museums visited during
European meteorite research tour for their help and support and Ms. Mary Sohn for grammar
corrections to the manuscript.
Finally I would like also to thank my family, especially my parents Libuše Kohoutová and
Vladimír Kohout, and my friends for their support throughout the years of my studies.
This work would not be possible without financial support by the Academy of Finland, Sohlberg
Delegation, Väisälän Foundation and Emil Aaltonen Foundation.
The Ph.D. studies were carried out under joint supervision agreement (co-tutelle) between the
Faculty of Science at the University of Helsinki and the Faculty of Science at Charles University in
Prague.
6
Abstract
Together with cosmic spherules, interplanetary dust particles and lunar samples returned by
Apollo and Luna missions, meteorites are the only source of extraterrestrial material on Earth. They
represent samples of various space bodies from asteroids to other planets. Some are remains of
parent bodies, which completely disintegrated during giant collisions and no longer exist in the
Solar System.
The physical properties of meteorites, especially their magnetic susceptibility, bulk and grain
density and porosity, have wide applications in meteorite research such as meteorite classification,
studies of their origin, level of terrestrial weathering, shock history and in the estimation of the
physical appearance of their parent bodies – asteroids. For example, the comparison of a meteorite’s
density, porosity or magnetic susceptibility to that of a compositionally similar asteroid may reveal
its internal structure. For such purposes, an expanded database of meteorite physical properties was
compiled with new measurements done in meteorite collections across Europe using a mobile
laboratory facility.
However, the scale problem may bring discrepancies in the comparison of asteroid and meteorite
properties. Due to inhomogenity, the physical properties of meteorites studied on a centimeter or
millimeter scale may differ from those of asteroids determined on kilometer scales.
Further difference may arise from shock effects, space and terrestrial weathering and from
difference in material properties at various temperatures. As demonstrated on rock magnetic studies
of the Neuschwanstein meteorite, compared to room temperature, sulphides present in
extraterrestrial materials have distinct magnetic properties with newly discovered magnetic
transitions at temperatures of the “cold” Solar System environment. This draws significant
constraints on modeling the interaction of minor Solar System bodies with interplanetary magnetic
fields.
Close attention was given to the reliability of the paleomagnetic and paleointensity information in
meteorites. A modified method, based on coercivity distribution of the remanent magnetization
efficiency, was tested on various terrestrial and extraterrestrial samples. The results show that
impact related shock effects on remanent magnetization can be distinguished or atypical magnetic
carriers can be identified. Further, the reliability of the thermoremanent magnetization efficiency as
the paleointensity tool was studied and calibrated for various minerals of different grain sizes.
These studies give us a tool for reliable interpretation of magnetic information carried in
extraterrestrial materials. Such information provides constraints on ancient magnetic field
intensities
and
on
the
evolution
of
minor
7
bodies
in
our
Solar
System.
The thesis consists of an overview and the following original articles referred to in the text by their
Roman numerals:
I. Kohout, T., Kletetschka, G., Elbra, T., Adachi, T., Mikula, V., Pesonen, L.J., Schnabl, P. and
Slechta, S., 2008. Physical properties of meteorites – applications in space missions to asteroids.
Meteoritics & Planetary Science, 43, 1009-1020.
II. Kohout, T., Kletetschka, G. and Pesonen, L.J., 2009. From Laboratory Scale to Astronomical
Scale – Implications on Physical Properties of Hayabusa Sample Return from (25143) Itokawa
Asteroid. Astronomical Society of the Pacific Conference Series, accepted.
III. Kohout, T., Kosterov, A., Jackson, M., Pesonen, L.J., Kletetschka, G. and Lehtinen, M., 2007.
Low-temperature magnetic properties of the Neuschwanstein EL6 meteorite. Earth and Planetary
Science Letters, 261, 143–151.
IV. Kohout, T., Kletetschka, G., Donadini, F., Fuller, M., Herrero-Bervera, E., 2008. Analysis of
the natural remanent magnetization of rocks by measuring the efficiency ratio through alternating
field demagnetization spectra. Studia Geophysica et Geodaetica, 52, 225-235.
V. Kletetschka, G., Fuller, M.D., Kohout, T., Wasilewski, P.J., Herrero-Bervera, E., Ness, N.F. and
Acuna, M.H., 2006. TRM in low magnetic fields: a minimum field that can be recorded by large
multidomain grains. Physics of the Earth and Planetary Interiors, 154, 290-298.
VI. Kohout, T., Donadini, F., Pesonen, L.J. and Uehara, M., 2010. Rock magnetic studies of the
Neuschwanstein EL6 chondrite – implications on the origin of its natural remanent magnetization.
Geophysica, 45, 3-19.
Article I is reprinted from Meteoritics & Planetary Science with permission from The Meteoritical
Society. Article II is reprinted from Astronomical Society of the Pacific Conference Series with the
permission from the Astronomical Society of the Pacific. Articles III and V are reprinted from
Earth and Planetary Science Letters and Physics of the Earth and Planetary Interiors respectively
with the permission from Elsevier. Article IV is reprinted from Studia Geophysica et Geodaetica
with permission from Springer. Article VI is reprinted from Geophysica with permission from the
Geophysical Society of Finland.
8
Authors’ contribution to the publications
I. Tomas Kohout was a leading author in this publication. He was responsible for scientific and
administrative preparation and organization of the meteorite museum tour, measurements in the
museums and for meteorite sample selection. After the measurements were completed he processed
the data, merged those with the previous measurements and did the interpretation. He also
significantly contributed to the methodology of the remote detection of the asteroidal susceptibility
outlined in the paper. He did most of the manuscript writing and was responsible for the manuscript
handling during the review and proof stage.
II. Tomas Kohout was a leading author in this publication. He outlined the scientific objectives of
the research, revised the old database of the meteorite physical properties and selected the most
reliable entries with respect to the scientific objectives of the Hayabusa space mission and its target
– Itokawa asteroid. Tomas also took lead in the evaluation of the possible magnetic and other
physical properties studies of the Itokawa asteroid sample return. He did most of the manuscript
writing and was responsible for the manuscript handling during the review and proof stage.
III. Tomas Kohout was a leading author in this publication. He outlined the scientific objectives of
the research. Tomas did the scientific experiments during his visit at Institute for Rock Magnetism,
University of Minnesota and subsequently did the data processing. He took also lead in the
interpretation of the results. He did most of the manuscript writing and was responsible for the
manuscript handling during the review and proof stage.
IV. Tomas Kohout was a leading author in this publication. With the help of co-authors gathered
experimental data to demonstrate the use of the proposed technique. Tomas also did part of the
experiments and data processing. He did most of the manuscript writing and was responsible for the
manuscript handling during the review and proof stage.
V. The major contribution of Tomas Kohout to this study is the active participation on the scientific
laboratory experiments. He also participated to the interpretation of the results and he was actively
contributing to the main author during manuscript writing, review and proof stage.
VI. Tomas Kohout was a leading author in this publication. He outlined most of the scientific
objectives of the publication and did most of the scientific experiments and data processing. He has
9
also major role in the interpretation of the results. He did most of the manuscript writing and is
responsible for the manuscript handling during the review and proof stage.
10
1. Introduction to meteorites and their parent bodies – asteroids and planets
Almost everyone has seen a falling meteor in the night sky. This phenomena is related to
meteoroids, small dusty particles released by comets visiting inner Solar System. Meteoroids are the
residuum of the comet’s tail which occurs during the comet flyby of the Sun. Once the meteoroid
falls into the Earth’s atmosphere, it makes an ionized trail. This shiny trail is called a meteor.
Sometimes, the Earth crosses a “fossil” comet’s dusty tail made of numerous meteoroids. In this
case, we observe a meteor shower. If the trail is of unordinary brightness, it is called a fireball.
Fireballs are usually caused by larger interplanetary objects – centimeters to tens of meters in size.
These objects may already be classified as small asteroids. If part of a fireball survives the
atmospheric entry and reaches the Earth’s surface, it is called a meteorite. Our collections have a
vast range of meteorite types. A comprehensive overview of meteorite classification is given by
Norton (2002) and below I will highlight the main classification principles and compositional
characteristics.
In general, meteorites are divided in three major groups: stony, stony-iron and iron ones. Stony
meteorites are subsequently divided into primitive stony meteorites – chondrites, and into
differentiated stony meteorites – achondrites.
The composition of chondrites represents mainly undifferentiated primitive material of the early
Solar System nebula. The name “chondrite” is derived from the texture of these meteorites. Almost
all chondrites contain sub-spherical or sometimes ellipsoidal, 0.1 to 4 mm in diameter, structures
called chondrules. There is still ongoing debate regarding the origin of chondrules (Sears, 2004).
The two main competitive theories are the origin by rapid crystallization in the early solar nebula or
the production of chondrules during impact processes. There is a single group, CI chondrites, that
contains no chondrules, but is chemically related to the other chondrites and therefore classified as a
chondrite without chondrules. Several clans divide the chondrite class. These are the enstatite
chondrites (E), ordinary chondrites (OC), carbonaceous chondrites (C) and Rumuruti chondrites
(R), arranged here by their iron oxidation level (Femetal/Fetotal) from the most reduced (E) to the most
oxidized (R). The chondrite clans are further divided into groups based upon their mineralogical
and chemical properties. The OC clan is divided into H (high), L (low), and LL (low-low) groups
based also on their amount of non-oxidized iron (Femetal+FeS/FeO). The E clan, in a similar way, is
divided into two groups, EH (high) and EL (low). The C clan is composed of a total of seven groups
(CI, CM, CR, CV, CO, CK and CH) with CI being the most pristine group. The division into C
chondrite groups is based not only on the oxidation level, but is more complex, taking into account
other mineralogical, chemical and textural criteria. The chondrites are additionally classified in six
11
petrographic types based upon their metamorphic degree (E, OC and R chondrite types 3-6 with
type 3 showing the least metamorphic features) or aqueous alteration (C types 1-3 with type 3
showing the least alteration). These trends are summarized in Table 1, 2 and Fig. 1.
Table 1: Chondrite types and subtypes with their oxidation/reduction state, chondrule appearance
and observed range of alteration or metamorphism. From Norton (2002), modified.
1
Chondrite
2
3
4
5
6
group and
petrographic
< 200°C
400°C
600°C
Aqueous alteration
type
Chondrules
Carbonaceous
CI
chondrites
CM
Absent
Sparse
700°C
> 750°C
Thermal metamorphism
Abundant, distinct
Increasingly indistinct
CR
CO
CV
CK
R chondrites
R
Ordinary
LL
chondrites
L
H
Enstatite
EL
chondrites
EH
Table 2: Chondrite subtypes with their metal, total iron, fayalite and forsterite abundances. From
Norton (2002).
Metal (wt%)
Total iron (wt%)
Fa (mole%)
Fs (mole%)
EH, EL
17-23
22-33
<1
0
H
15-19
25-38
16-20
14-20
L
1-10
20-23
21-25
20-30
LL
1-3
19-22
26-32
32-40
Group
12
Figure 1: Chondrite types and subtypes with their Femetal+FeS/FeO ratio. From the figure, it is
apparent that the carbonaceous chondrites are the most oxidized while the enstatite chondrites are
the most reduced. From Norton (2002).
Differentiated stony meteorites, achondrites, are rarer. They are further divided into four
subclasses: asteroidal, martian, lunar and primitive achondrites (Table 3). Melting and
differentiation of parent bodies changed their composition so that their elemental abundances are no
longer solar. Thus, the achondrites are samples of the igneous rocks from other Solar System
bodies. All differentiated meteorites lack chondritic textures.
Table 3: Division of achondrite class into subclasses and groups.
Achondrite subclass
Asteroidal
Achondrite groups
basaltic achondrites – Howardites, Eucrites, Diogenites (HED)
Angrites
Aubrites
Ureilites
Brachinites
Martian
Shergottites, Nakhlites, Chassignites (SNC)
Lunar
Lunaites
Primitive
Acapulcoites, Lodranites, Winonaites
The asteroidal achondrites are further divided into: basaltic achondrites, Angrites, Aubrites,
Ureilites and Brachinites, each representing differentiated products of unique parent bodies. The
basaltic achondrites consists of Howardites, Eucrites and Diogenites (HED) with their
compositional characteristics being similar to the asteroid 4-Vesta.
13
The martian achondrites: Shergottites, Nakhlites and Chassignites (SNC) are highly
differentiated. Due to their mineralogical and chemical composition, composition of gas isotopes
and crystallization age of 1.3 billion years (too low for asteroidal origin), SNCs are believed to be
fragments of martian crust catapulted by a large impact. Similarly, lunar meteorites have
compositions similar to the lunar crust.
The subclass of rare primitive achondrites (containing Acapulcoites, Lodranites and Winonaites)
is exceptional in that sense, that even though it shows igneous textures it keeps primitive elemental
abundances.
Iron meteorites are highly differentiated meteorites which possibly represent cores of large
asteroid parent bodies broken apart by catastrophic collisions. Iron meteorites show a texture called
the Widmanstätten structure. It is the result of the exsolution of two main iron-nickel phases: lownickel kamacite and high-nickel taenite. The pattern appears upon etching with diluted nitric acid or
ferric chloride because the kamacite dissolves more readily in acid than taenite. According to their
FeNi phase composition the iron meteorites are divided into hexahedrites, octahedrites and ataxites.
The stony-iron meteorites, Pallasites, are one of the most beautiful meteorites, consisting of
roughly equal amounts of metal and silicates. Their origin can be thought of as an immiscible
emulsion, like oil and water. During differentiation, fractional crystallization should separate the
two major minerals, iron and olivine, so that they crystallize separately in distinct parts of an
asteroid parent body. To mix iron core material with pure olivine mantle cumulate requires one of
two processes. Either solid crystalline olivine must settle into the still molten FeNi core or liquid
core metal must be forcibly injected into the olivine cumulate layer. It may have been assisted by
shock waves generated from surface impacts or by convective instability in the partially molten
core. Thus, Pallasites must have formed after differentiation but before complete solidification of
the core and mantle.
Asteroids are minor, rocky bodies of our Solar System. Their diameter varies from several
meters to hundreds of kilometers. Most of them are orbiting between Mars and Jupiter, forming the
main asteroid belt, or in jovian L4 and L5 Lagrangian points forming “Trojans” (Fig. 2). However,
some are orbiting on eccentric trajectories and can cross the Earth’s orbit. The reflectance
spectroscopy of asteroids proved to be a powerful tool in the characterization of asteroid
composition and classification. The extended taxonomy (Tholen, 1984; modified by Bus and Binzel,
2002) defines a total of 26 classes of the asteroid reflectance spectra.
14
Figure 2: Inner Solar System with position of main asteroid belt and Trojan asteroids (asteroids
residing in L4 and L5 Lagrangian points of stability, which lie 60° ahead of and behind Jupiter.
They are thought to be as numerous as the asteroids of the main belt). From Wikipedia
(www.wikipedia.com)
The overview of the spectral, as well as of mineralogical and textural similarities and
discrepancies between meteorites and asteroids, is well compiled in Norton (2002) and in Sears
(2004). The spectra of the S-class asteroids are similar to the silicate-rich ordinary chondrite group
or to stony irons. The C-class contains asteroids which are rich in carbonaceous material and
volatiles and have spectral features similar to some carbonaceous chondrite classes. The M-class
shows spectra similar to those of metal. Thus iron meteorites, or E chondrites (as their spectra are
dominated by metals), are possible equivalents.
15
Figure 3: The comparison of the reflection spectra of the Rennazzo CR2 chondrite and the main
belt asteroid 2-Pallas. The almost perfect match suggests that the 2-Pallas may be the source body
of CR chondrites. From Norton (2002)
However, when analyzing the whole spectral curve, an exact match between asteroids and
meteorites is very rare. Only few meteorite classes were linked to certain asteroids with high
confidence. The HED achondrites closely resemble the compositional characteristics of asteroid
6-Vesta. The H chondrites, in their spectral features, are very similar to asteroid 6-Hebe, L
chondrites to Flora family asteroids and LL chondrites to Gefion family asteroids. The spectra of
CR chondrites almost matches that of 2-Pallas (Fig. 3). CM chondrites are close to 1-Ceres. Several
near-Earth asteroids show spectral similarities to L/LL chondrites (433-Eros and 1685-Toro are
similar to L type chondrites, while 25143-Itokawa is similar to LL type chondrites (Fig. 4); see also
Vernazza et al. (2008). In addition, meteorites coming from large bodies as SNCs proved to
originate on Mars and Lunaites (lunar meteorites) from our Moon.
Figure 4: The composition of the Bjurböle L/LL4 meteorite (left) is similar to the 25143-Itokawa
asteroid (right) which was recently visited by the Hayabusa space probe.
However, in most cases, the spectral match is less apparent. There are several explanations for
this. First, the effects of long term exposure to cosmic rays (called space weathering) change the
properties of asteroidal surfaces. Second, the surface of asteroids (called regolith) may be
contaminated by materials of other bodies through collisions and impact processes. The third factor
16
may be related to our Earth. Its stable position within our Solar System, presence of the atmosphere
and weathering on the surface act as a filter allowing only objects on Earth-crossing trajectories, of
sufficient material strength (enough that the whole object does not disintegrate in the atmosphere
during the fall) and with resistance to weathering to reach our hands. This may partially explain
how 80% of our meteorite collections consist of ordinary chondrites (compared to C chondrites of
relatively high mechanical strength and terrestrial weathering resistance), while carbonaceous
meteorites make up only around 4%. However, C asteroids are one of the most common in the
asteroid belt compared to much fewer S type asteroids with spectral similarities to known ordinary
chondrites.
The internal structure of asteroids and their evolution is reflected in their physical properties. As
discussed in the following text, the density, porosity and magnetic susceptibility data give
constraints on asteroidal compositions while the paleomagnetic and paleointensity investigations of
meteorites give constraints on the size and evolution of their ancient parent bodies.
Asteroid physical properties can be estimated by remote sensing and by studying meteorite
equivalents. There is not a general agreement regarding the internal structure of stony asteroids.
Some of them may resemble the structure called a “rubble-pile” while the others may be close to an
“onion-skin” model. Rubble-piles represent loose conglomerates of either primordial material or
reassembled products of catastrophic impacts (e.g. 25143-Itokawa). Onion-skin-like asteroids
represent large, compact, differentiated bodies (e.g. 6-Vesta). Thus, a single asteroid body can be a
source of various types of meteorites (Fig. 5).
Brecciated, highly porous, stony meteorites may come from surface regolith, while compact,
highly metamorphosed meteorites of the same class can be products of processes in parent body
interiors (Wilkison et al., 2003).
However, while comparing meteorites to asteroids or planets, a scale problem (as discussed in
II) must be taken into account. There are differences in the properties of the mm sized sample
returns vs. cm or dm sized meteorites vs. m to 102 km sized asteroids (see cover page picture). This
is because of asteroidal inhomogenity from kilometer down to sub millimeter scale. Similar
inhomogeneity, but in cm to sub-mm scale, exist in meteorites. Some meteorites are breccias
composed of cm sized clasts and some contain cm to mm sized inclusions or chondrules. Thus, the
potential difference in observations or measurements on various scales is obvious.
17
A
B
Thermal metamorphism caused by shortlived radioisotopes and frequent impacts
C
E
D
Figure 5: The model of evolution of an asteroid. The original chondritic parent body (A) is
differentiated during thermal metamorphism into an onion-shell structure (B, numbers indicate
chondritic petrographic types). Subsequently, a giant collision occurs, causing catastrophic
disruption (C). Parts of the materials from collided objects finally reassemble by mutual gravity (D)
forming a heterogeneous and highly porous rubble-pile structure (E). From Norton (2002),
modified.
2. Physical properties of meteorites – measurements and applications
The expanded database of meteorite physical parameters is one of the primary outcomes of my
doctoral studies. As will be discussed in the following chapters, the data have numerous
applications in the meteorite and planetology research.
In general, the meteorites are rocks of unique compositions distinct from terrestrial ones.
Moreover, they were never exposed to such an oxidizing environment as on present-day Earth and
thus are not in chemical equilibrium with the terrestrial atmosphere. This results in extreme
sensitivity of meteorites to weathering. This process is even accelerated at elevated temperatures
(i.e. during thermomagnetic measurements, thermal demagnetization or paleointensity studies
involving heating) or during exposure to various oxidizing agents (i.e. tap water with dissolved
atmospheric oxygen and other gases like chlorine).
18
Thus, it is essential to apply harmless methods to minimize the mineralogical changes in
meteorites during our experiments. Paper I describes the development and calibration of portable
instrumentation used for the measurements of the meteorite bulk physical properties during the
meteorite research tour to the European museums (Fig. 6). The use of glass beads for meteorite
volume measurement (eliminating the need for any liquid as in conventional Archimedean method)
and the use of low pressure air pycnometer for meteorite grain volume measurement (using ambient
air as the pore penetrating medium) were essential for successful density and porosity
determinations.
Geological survey of Estonia, Tallinn (1) – H. Pärnaste
Tartu University, Estonia (2) – J. Plado
Geology and Mineralogy Museum, Vilnius, Lithuania (3) - B.Poshkiene
Vilnius University, Lithuania (4) - E. Rudnickaite, G. Motuza
Planetarium and Observatory Olsztyn, Poland (5) – J. Biala, J. Szubiakowski
Geological Institute of Hungary, Budapest, Hungary (6) – O. Kákay-Szabó
Eötvös L. University, Budapest, Hungary (7) – T. Weiszburg
Museum of Natural History, Budapest, Hungary (8) – A. Embey-Isztin
National Museum, Prague, Czech Republic (9) – M. Bukovanska
Chemical University, Prague, Czech Republic (10) – A. Martaus, B Kratochvil
Humboldt University of Berlin, Germany (11) - A. Greshake
University of Münster, Germany (12) – A. Bischoff
University of Oslo, Norway (13) – G. Raade
Swedish Museum of Natural History, Stockholm, Sweden (14) – J. O. Nyström
Figure 6: A map showing the collections and museums visited during the 2005 meteorite research
tour together with the names of local curators.
Use of glass beads was allowed in all but one institution (here it was replaced by the
conventional Archimedean method using ethanol). The disadvantage of the glass-bead method is
that it is slower (10-15 minutes per sample is required to bring the volume error below 0.1 cm3 as an
average of 10 individual measurements is typically needed), requires gaining of proper
measurement experience and is sometimes “a bit messy” (the tiny glass beads tend to “fly” and
spread around the laboratory).
The air pycnometer proved to be a practical instrument for meteorite grain volume
measurements. The instrument is actually a refurbished old Notari pycnometer, originally designed
for grain volume measurements of minerals and soil porosity determinations. Compared to
advanced helium pycnometers currently used in petrophysical laboratories, it has a lower resolution
(0.1 cm3 in the 5-30 cm3 volume range), which is still sufficient for our database purposes.
However, it does not require any gas supply (i.e. helium), and thus can be easily transported and
installed in remote facilities. Use of ambient air prevents contamination of pore space by foreign
19
chemical agents. The measurement time per sample is approximately 1-2 minutes. As other
pycnometers, it is sensitive to ambient temperature drift and also to sudden atmospheric pressure
changes, and thus proper attention should be taken to minimize those effects during the
measurements. The instrument should be also handled carefully during transportation as it contains
mercury in the pressure gauge. It is the only equipment from our mobile laboratory not suitable for
air freight.
For magnetic susceptibility measurements the portable Hämäläinen TH-1 susceptibility meter
was used. The instrument was kindly donated to our laboratory by the Outokumpu company. The
advantage of this instrument is a large 12 cm vertical coil suitable for measurements of larger,
formless meteorite samples.
Prior to the meteorite measurements, the instrument was cross-calibrated with the laboratory
RISTO 5 and Agico KLY-3 susceptibility meters using a set of rocks as well as artificial samples of
various susceptibilities. The homogeneity of the field along the axis of the coil was mapped using a
calibration sample (made of gypsum with dispersed iron particles). Knowledge of the position and
length of the homogenous field region inside the coil is essential for determination of the limiting
sample dimensions and optimal measurement position.
The disadvantage of this instrument is lower sensitivity threshold and resolution (both
~ 10-6 m3/kg). This was a serious issue in most measurements of the weaker, small achondrite and
carbonaceous chondrite samples. In other cases, there were no significant difficulties with the
measurements.
Trials were done to measure the magnetic remanence of samples during the museum tour. For
this purpose, a portable Schoenstedt PSM-1 remanence meter was used (also donated by the
Outokumpu company). The instrument incorporates a flux-gate sensor located at the far end of the
sample shaft to measure the magnetic moment of samples. The instrument was tested prior to the
meteorite measurements using a set of calibration rock samples. However, there was high
sensitivity to noise in low measurement ranges. Partly due to this reason, as well as due to unknown
NRM (Natural Remanent Magnetization) origin in the meteorite samples (extraterrestrial vs.
artificial or viscous overprint), only few meteorite measurement trials were done and the effort was
rather focused on other measurements.
During the meteorite tour, the physical properties of 179 individual meteorites were measured
(Fig. 7). The data, processing and results, as well as the comparison to existing data in similar
databases, are described in I. The data agree well with those measured previously in Finland
(Kukkonen and Pesonen, 1983, Pesonen et al., 1993, Terho et al., 1993ab, see Appendix and Figs. 1
and 2 in I) as well as with those by Consolmagno and Britt (1998), Flynn et al. (1999), Wilkison
20
and Robinson (2000), Britt and Consolmagno (2003), Wilkison et al. (2003) and Smith et al. (2006)
– densities and porosity, or Rochette et al. (2003) – magnetic susceptibility of ordinary chondrites,
Rochette et al. (2008) – non-ordinary chondrites, and Rochette et al. (2009) – achondrites. The new
results are shared with the scientific community and thus the data in Rochette et al. (2008 and 2009)
already include the new values obtained during our meteorite tour.
Figure 7: Tomas Kohout and Tiiu Elbra performing the measurements together with Prof.
Gediminas Motuza at Vilnius University.
The database by Rochette et al. is much larger. However, our database has several additional
features. One is that our database contains not only apparent, but also true susceptibility values
(shape corrected for the demagnetization factor using approach by Osborn (1945), incorporating
ellipsoidal shape model). This correction does not make a significant difference at apparent
susceptibility values below 5 x 10-5 m3/kg or 0.1 SI. However, at higher susceptibility values and
more elongated meteorite shapes, this difference between apparent and true susceptibility may reach
high percentages (Table 1 in I). The methodology is discussed in detail in I.
Early studies show that the magnetic susceptibility (Kukkonen and Pesonen, 1983, Pesonen et
al., 1993, Terho et al., 1993ab, Rochette et al., 2003, 2008, 2009) and the bulk or grain density
(Consolmagno and Britt, 1998, Flynn et al., 1999, Wilkison and Robinson, 2000, Britt and
Consolmagno, 2003, Wilkison et al., 2003, Smith et al., 2006) of various meteorite clans and groups
occupy characteristic values with quite uniform distribution, which is further supported by our new
data (Fig. 1 and 2 in I).
21
The magnetic susceptibility of meteorites is related to the amount of magnetic minerals. Thus I
will present a short overview of meteorite magnetic mineralogy (Table 4).
Table 4: Main ferro and ferrimagnetic minerals (at room temperature) found in meteorites with
their chemical formula, crystal and magnetic structure, saturation magnetization (Ms) and Curie
temperature (Tc). AC-Acapulcoites, ANG-Angrites, AUB-Aubrites, C-carbonaceous chondrites,
E-enstatite chondrites, HED-Howardites, Eucrites, Diogenites, LUN-Lunaites, OC-ordinary
chondrites, R-Rumuruti chondrites, SNC- Shergottites, Nakhlites, Chassignites, URE-Ureilites.
Mineral
Kamacite
Chemical
Crystal
formula
structure
FeNi
cubic, bcc
Magnetic
Ms
structure (Am2/kg)
ferro
150-220
Tc
Meteorite group
(°C)
740-780
AC, C, E, OC,
R
Taenite
FeNi
cubic, fcc
ferro
100-600
HED, AUB,
LUN, OC
Tetrataenite
FeNi
cubic
ferro
550
HED, AUB,
LUN, OC
Magnetite
Cohenite
Fe304
cubic
(Fe,Ni)3C orthorhombic
ferri
92
ferri
580
ANG, C, SNC
205-215
AUB, C, E,
HED, URE
Schreibersite (Fe,Ni)3P
tetragonal
ferri
100
>455
AUB, C, E,
HED, URE
Pyrrhotite
Fe(1-x)S
hexagonal
antiferro
monoclinic
ferri
15-20
290-320
ANG, C, R,
SNC
Magnetic properties of enstatite chondrites, CO, CR and CH carbonaceous chondrites and
ordinary chondrites are dominated by FeNi alloys (Nagata, 1979, Kukkonen and Pesonen, 1983,
Wasilewski, 1988, Morden and Collinson, 1992, Wasilewski et al., 2002). Depending on the Ni
concentration, the main FeNi minerals are kamacite (D form < 7% Ni), taenite (J form > 7% Ni) and
tetrataenite (ordered J" form 43-52% Ni).
The redox conditions cause iron to be oxidized to monoclinic pyrrhotite Fe7S8 or magnetite
Fe3O4, or reduced to cohenite (Fe,Ni)3C or schreibersite (Fe,Ni)3P. Magnetite, cohenite and
schreibersite have been reported in carbonaceous chondrites, cohenite and schreibersite can be
found in enstatite chondrites and pyrrhotite is dominant in Rumuruti chondrites (Rubin, 1997,
Brearley and Jones, 1998). The presence of magnetite has been also described in a few
22
unequilibrated ordinary chondrites (Krot et al., 1997, Menzies et al., 2002) and in chondrite shock
veins (Chen et al., 2002).
The magnetic properties of stony achondrites are similarly dominated by FeNi alloys, usually by
low Ni kamacite (Nagata, 1979, Sugiura and Strangway, 1988). In contrast, metal is absent in
martian meteorites, where the magnetic properties are predetermined mainly by the presence of
magnetite and pyrrhotite (Rochette et al., 2005). Additionally, a minor presence of taenite and
tetrataenite were observed in some HEDs, Aubrites and lunar meteorites. Schreibersite and cohenite
were observed in Aubrites, HEDs and Ureilites (Mittlefehldt et al., 1998). Pyrrhotite (Kurat et al.,
2004) or magnetite (Floss et al., 2003) are present in Angrites, in association with metal. Recently,
shock-produced metallic nanoparticles have been observed in martian meteorites (Van de Moortele
et al., 2007, Hoffmann et al., 2008).
The amount of magnetic minerals is reflected in meteorite susceptibility values (Rochette et al.,
2003, 2008, 2009). The lowest susceptibility is reached by SNC (10-100 x 10-8 m3/kg) and HED
(10-1000 x 10-8 m3/kg)
achondrites.
Aubrites
also
have
low
susceptibility
values
(400-3000 x 10-8 m3/kg). The chondrite class has higher susceptibilities in the range of
4000-80000 x 10-8 m3/kg
(with
the
exception
of
R-chondrites
reaching
a
range
of
100-160 x 10-8 m3/kg) and stony-irons and irons occupy the highest susceptibility range
(100000-2000000 x 10-8 m3/kg). However, it is difficult to measure the true magnetic susceptibility
of stony-irons and irons due to the extreme shape effects (as discussed in I), and thus the values
contain high level of uncertainty. Perhaps, the use of an astatic magnetometer or a magnetic balance
may overcome this difficulty.
The lowest susceptibility values among ordinary chondrites occupy the LL chondrite group with
a range of approximately 300-4000 x 10-8 m3/kg, followed by the L chondrite group
(4000-14000 x 10-8 m3/kg) and the H chondrite group (14000-46000 x 10-8 m3/kg). The
susceptibility of the enstatite chondrite clan falls mostly in the range of 46000-80000 x 10-8 m3/kg.
Urelites occupy a similar susceptibility range (6000-15000 x 10-8 m3/kg) as L type chondrites.
The magnetic susceptibilities of various carbonaceous chondrite groups overlap and are similar
to those of ordinary chondrites. However, compared to ordinary chondrites, the carbonaceous
chondrites generally have lower bulk and grain densities (Consolmagno and Britt, 1998, Flynn et
al., 1999, Wilkison and Robinson, 2000, Britt and Consolmagno, 2003, Wilkison et al., 2003, Smith
et al., 2006). The CM and CV groups roughly occupy the range of 400-4000 x 10-8 m3/kg, while the
CO, CK and CI groups fall mostly in the range of 2500-6300 x 10-8 m3/kg. The ungrouped C3-4
meteorites are characterized by susceptibilities in the range of 3100-10000 x 10-8 m3/kg. The CR
group has values around 10000 x 10-8 m3/kg. The highest susceptibility values among carbonaceous
23
chondrites (comparable to those of enstatite chondrite clan) occupy the CH group with a range of
16000-63000 x 10-8 m3/kg.
These findings provide an aid in meteorite and asteroidal research. For example, magnetic
susceptibility can be used in rapid preliminary meteorite classification (Terho et al., 1993ab,
Rochette et al., 2003, 2008 and 2009) or modeling of asteroidal magnetic anomalies (Pesonen et al.,
1993).
In the study published in I, a further step was taken to determine magnetic susceptibility of an
asteroid. Determination of the asteroidal susceptibility is not a trivial task, but is possible. Three
possible methods were evaluated. Those include asteroidal susceptibility determination from an
induced magnetization by interplanetary magnetic field (IMF) using an orbiting space probe, active
measurement using a surface probe (AC coil) attached to a lander, or direct laboratory measurement
on a sample return from asteroid. While the second and third option may provide more accurate
measurements, the advantage of the first method is that the susceptibility of the whole asteroid is
determined. This is important because the surface material, regolith, may not be representative of
the whole asteroid composition as it is often affected by space weathering and may be also
contaminated by the debris of foreign impacting bodies (as already discussed in the Introduction
and also in more in detail in II).
Once magnetic susceptibility is successfully determined, the amount and nature of the magnetic
minerals can be inferred. Based on the true susceptibility (shape corrected in the same way as for
meteorites), asteroids can be classified in a similar way as meteorites are. The distribution of
magnetic susceptibility among various asteroid compositions is expected to reflect the distribution
of their meteorite equivalents. Similarly as for meteorites, the range of the susceptibilities of some
asteroid classes may overlap. Additionally to reflectance spectroscopy (Bus and Binzel, 2002) and
other chemical and mineralogical remote sensing methods, magnetic classification may refine
matches among meteorite equivalent candidates (I and II).
Similar measurements done on meteorites (I) may be performed on a sample return from an
asteroid. The methods are outlined in more detail in II. For example, the hysteresis properties can
be determined and used for the classification purposes (Sugiura, 1977, Pesonen et al., 1993, Fig 2
in II or Fig. 3 in VI). Again, the scale effect as outlined above has to be taken into account in this
case.
The knowledge of mean densities and porosities of various meteorites can provide information of
their parent body internal structure. For example, the internal structure of asteroid 243-Ida is
discussed in the review by Chapman (1996). It is hard to find a compositional meteorite equivalent
to Ida. Ida is an S type asteroid with spectral similarities to ordinary chondrites or stony-irons. Here,
24
I present a simple comparison of Ida’s bulk density (2000-3100 kg/m3) to grain densities of
ordinary chondrites (~ 3500 kg/m3, Britt and Consolmagno, 2003, I) or stony-irons (4500 kg/m3,
Britt and Consolmagno, 2003, I) which gives a total porosity around 30% or 55% respectively with
the latter value to be less likely. However, if a certain fraction of icy material is considered within
Ida’s composition, the overall porosity decreases. Leliwa-Kopystynski et al. (2008) assumed half of
the Ida’s volume to be composed of ice of 940 kg/m3 density and other half of chondritic material
resulting on overall porosity around 20%. However, it is not specified whether grain or bulk density
was used by Leliwa-Kopystynski et al. (2008), and hence whether macroporosity (intrinsic to
ordinary chondrite material) is included or excluded from their estimate.
Wilkison et al. (2002) and Wilkison et al. (2003) compared the bulk density of 433-Eros
(2670 kg/m3; target of NEAR space probe) to the average bulk density of ordinary chondrites
(~ 3400 kg/m3) and estimated ~ 20% macroporosity for Eros and an additional ~ 6% microporosity
intrinsic to ordinary chondrite material.
A similar approach was applied by Abe et al. (2006) to 25143-Itokawa (target of Hayabusa space
probe, partly discussed also in II). The bulk density of Itokawa was determined from Hayabusa
observations to be 1950 kg/cm3. Compared to the bulk density (3190 kg/m3) of LL chondrites
(having reflectance spectra similar to those of Itokawa) the macroporosity of Itokawa was
determined to be around 40%. However, the microporosity intrinsic to LL chondrites (usually only
a few percent, but may reach values around 20% in some samples such as Bjurböle) is not discussed
in this study. Thus, the total porosity of Itokawa may be 50% or even slightly more, revealing the
truly rubble-pile structure of Itokawa.
3. Meteorites in the “cold” interplanetary environment
During the rock magnetic studies of the Neuschwantein EL6 meteorite, an abrupt change in
susceptibility at ~ 150 K was observed (Fig. 1 in III). This feature was repetitive but its nature was
not well understood. The iron bearing sulphides (troilite FeS, daubreelite FeCr2S4, and alabandite
(Mn,Fe)S) identified in the meteorite through mineralogical (Bischoff and Zipfel, 2003 – optical and
electron microscopy study) and Mössbauer analysis (Hochleitner et al., 2004) were considered as
the candidate phases responsible for this magnetic susceptibility anomaly. The change in
susceptibility at ~ 150 K is close to the Curie temperature Tc ~ 170 K of the synthetic daubreelite
(FeCr2S4) reported by Tsurkan et al. (2001a). Thus, a question raised whether the ~ 150 K feature
can be related to the daubreelite within the Neuschwanstein meteorite. A study of various rock
magnetic parameters (including magnetic susceptibility and its field and frequency dependence,
25
hysteresis properties, FC (Field Cooled) and ZFC (Zero Field Cooled) induced and remanent
magnetization cycles) was done with the Neuschwanstein meteorite, as well as with selected
minerals (FeCr2S4 – daubreelite extracted from the Coahuila IIAB hexaedrite iron meteorite, FeS –
troilite extracted from the Bruderheim L6 chondrite and FeNi20 (20% of Ni) and FeNi24 (24% of
Ni) industrial alloys) at the Institute for Rock Magnetism at the University of Minnesota in order to
identify the nature of this feature. The details of the study are described in III. Results proved that
the daubreelite present in Neuschwanstein and its Tc is responsible for the ~ 150 K feature detected
in susceptibility data through additional magnetic transition Tm at ~ 70 K which is close to the Tm
detected in synthetic daubreelite (~ 60 K) reported by Tsurkan et al. (2001a). The study
demonstrated that the daubreelite significantly contributes to its magnetic properties below 150 K.
Further comparison of the Neuschwanstein’s FC and ZFC induced and remanent magnetization
curves to those of daubreelite (both natural and synthetic) and FeNi (Figs. 3 and 4 in III) reveal that
while FeNi controls the remanent magnetization properties, the induced magnetic properties are
dominated by daubreelite. This finding came as a surprise and should be considered while
interpreting the interactions of extraterrestrial materials with solar or artificial magnetic fields.
More detailed analysis of the properties of the natural daubreelite from the Coahuila meteorite
revealed features not reported before. The FC and ZFC curves of the remanent magnetization show
the presence of significant remanence at temperatures below Tm. However, warming above Tm
almost completely erases the low-temperature remanence: the moment for T > Tm is only ~ 1% of
the initial value, and moreover it is of the opposite sign (Fig. 4 in III).
Another surprise came while reviewing the troilite measurements. From the FC and ZFC curves
of the induced and remanent magnetization, a magnetic transition at Tm ~ 60 K is inferred (Figs. 3
and 4 in III). In susceptibility curves, this transition is characterized with peaks in real and
imaginary components, showing both frequency and field dependence. Below Tm, both saturation
magnetization and coercivity rapidly increase. The material becomes magnetically extremely hard
with coercivity around 200 mT (Fig. 7 in III) and saturation not fully reached even in a 5 T field
(Fig. 8 in III). Magnetic properties of troilite have been extensively studied (Muramaki and
Hirahara, 1958, Hirahara and Muramaki, 1958, Muramaki, 1959, Horwood et al., 1976, Li and
Franzen, 1996) but there are almost no low-temperature magnetic data for troilite available in
literature, and thus those finding are fundamental.
The above data suggest that this transition may involve a change in the orientation of the
antiparallel magnetic spins. A most likely candidate is canting of antiparallel spins below Tm, which
would result in an increase of magnetic susceptibility as well as of the induced and remanent
magnetization, similar to that observed in hematite when passing through the Morin transition from
26
below. The impossibility to reach saturation of the low-temperature phase is then explained by
random orientation of canted antiparallel spins in a powdery sample. However, it must be stressed
that the nature of this transition is not yet fully understood and needs further study.
The observed induced and remanent magnetic properties of troilite are typically one to two orders
of magnitude lower than those of daubreelite or FeNi, and thus hardly detectable in samples where
those phases are present in equal abundances (as in the Neuschwanstein meteorite).
Similar low-temperature transitions, as observed in daubreelite and troilite, are reported also in
alabandite (Petrakovski et al., 2002, Loseva et al., 1998, Heikens et al., 1977, Lines and Jones,
1966).
New questions rose from some observed differences between magnetic properties of natural
sulphides used in III and its synthetic analogues used in previously published work. For example,
the transition temperatures in extraterrestrial daubreelite are slightly different compared to
published values of synthetic samples in Tsurkan et al. (2001abc), (Fig. 2 in III). Another example
is that the artificially prepared troilite used during my recent unpublished work does not show all
the features observed in Bruderheim’s troilite (III). Some of these differences may be attributed to
the presence of additional substituting ions specific for extraterrestrial material (various amounts of
Mn were observed in extraterrestrial daubreelite). Other explanations may be the possible
inhomogenity of synthetic analogues, the structural differences in naturally and artificially grown
crystals, chemical variations within minor and trace elements present in the samples, weathering of
extraterrestrial material or different modal proportion of phases of interest present in the meteorite
samples. Thus, possible influences of the aforementioned factors should still be addressed in future
work.
As discussed above, these discoveries are directly related to the Solar System exploration as well
as to material science research. For example, the results are beneficial in understanding the
magnetic properties of extraterrestrial materials in a cold interplanetary environment.
As the sulphide compounds undergo various magnetic transitions at low temperatures, the bulk
magnetic properties of extraterrestrial material changes significantly compared to room temperature
conditions (Fig. 9). This opens a new way to view extraterrestrial materials and to interpret their
properties and interactions with magnetic fields in cold areas of our Solar System.
27
2.45
FC
ZFC
Mi (Am2/kg)
2.4
2.35
2.3
100
200
300
T (K)
Figure 9: FC (Field Cooled) and ZFC (Zero Field Cooled) curves of the induced magnetization of
the EL6 Daniel's Kuil meteorite (left). The Curie temperature (~ 170 K) and magnetic transition
(~ 60 K) of daubreelite can be identified. The daubreelite occurs usually in association with other
sulphides and kamacite (right). D-daubreelite, K-kamacite, T-troilite. The scale bar at the bottom
of the image indicates 20 m.
Daubreelite with its Tc ~ 150 K may be a significant magnetic mineral in cold environment.
However, warming above Tm almost erases the low-temperature remanence and results in the loss
of low-temperature magnetic information. Further heating through Tc results in magnetic
unblocking and loss of the magnetic information. Based on empirical observations as well as on
theoretical models (Spencer et al., 1989; Lim et al., 2005) the present surface temperatures of the
NEAs (Near Earth Asteroids) and asteroids within the main asteroid belt are above Tc where
daubreelite has paramagnetic properties. The thermal state of asteroid interiors (especially of
rubble-piles of high porosity, and thus of low thermal conductivity) is less clear due to limited
knowledge of their internal structure.
The icy Trans Neptunian Objects (TNOs) and bodies of outer Solar System reside in much
colder regions. Iron, chromium and manganese bearing sulphides are common not only in primitive
chondritic meteorites, but have been reported in interplanetary dust particles (IDP’s) (Rietmeijer,
2005, Dai and Bradley, 2001) and cometary dust (Zolensky et al., 2007, Lisse et al., 2006,
Jessberger, 1999). Their occurrence in such extraterrestrial materials is more abundant than metallic
phases. This makes the study fully relevant to the recently launched (2004) Rosetta (European
Space Agency) mission, which is due to arrive to comet 67P/Churyumov-Gerasimenko in May
2014 and enter its orbit. A lander is part of the mission and will land on the comet nuclei. Both
lander and orbiter are equipped with onboard magnetometers to map the cometary magnetic field
28
and monitor its interactions with solar wind. The mission will follow the comet’s approach towards
the Sun causing the ambient temperature conditions to vary. Thus, the knowledge of the magnetic
properties of sulphides present in extraterrestrial material and their variations with temperature is
essential to interpret magnetic data delivered by the Rosetta space mission.
Another outcome is improvement in basic material science knowledge of the studied compounds.
Especially, the discovery of the significant changes in Bruderheim’s troilite magnetic properties
below 60 K is novel and the mechanisms behind this behavior are not well understood. This feature
should be addressed in future research by the material science community.
4. Magnetic fields in the Solar System and paleofield estimates from meteorites
The Solar System is currently pervaded by various magnetic fields. Major sources are the Sun
and the planetary magnetic dynamos.
The present solar dipole magnetic field (closely aligned with rotation axis) is at the surface,
concealed by much stronger elements of toroidal fields. The magnetic flux at the surface is
concentrated into flux tubes of strength up to ~ 102 mT isolated by almost non-magnetic plasma
(Piddington, 1982, Solanki and Steiner, 1990). The solar dipole magnetic field rapidly decays
exponentially with cube of the distance. However, thanks to solar wind the inner Solar System is
filled with interplanetary magnetic field (IMF) of ~ nT strength. For example, without presence of
solar wind, the dipolar field would be two orders of magnitude smaller at 1 AU. The IMF is
dependent on solar activity and can reach order of magnitude higher values during solar magnetic
storms. IMF interacts with dynamo generated magnetic fields of planets. For example, the Earth has
magnetic dynamo and associated magnetosphere (area, where the magnetic field is dominated by
geomagnetic field) with surface magnetic fields around 30-60 T. The terrestrial magnetosphere
stretches approximately 63000-76000 km towards the Sun while the magnetic tail reaches up to
1300000 km (roughly 3.3 times the lunar orbit) in the opposite direction.
Jupiter is surrounded with a strong magnetosphere stretching seven million kilometers towards
the Sun and beyond Saturn’s orbit in the opposite direction (Cardall and Daunt, Russel and
Luhmann, 1997 pages 372-373). Similarly to terrestrial magnetosphere, its dimensions are highly
dependent on the solar wind strength and can shrink to 1/3 of its size during solar magnetic storms
(Cardall and Daunt). Inside jovian magnetosphere, the field can reach values of a few hundreds on
nT. For example, on Europa’s orbit the field variations reach ~ 150 nT (Alexeev and Belenkaya,
2009).
29
Objects in the main asteroid belt are thus outside the jovian magnetosphere, and even in the case
that a minor Solar System body on a extreme trajectory enters the jovian magnetosphere, it will not
be exposed to fields larger than 102 nT.
IMF may also interact with remanent fields of asteroids (as modeled by Omidi et al. (2002) or
observed by Hood (1994), Kivelson et al. (1995) and Wang et al. (1995) during Galileo flyby of
951-Gaspra and 243-Ida), but is not strong enough to remagnetize any remanence in the
extraterrestrial materials.
However, in the early Solar System evolution, the situation was different. For example, most of
the planetesimals, precursory bodies to present asteroids and meteorites, had liquid cores and
possible dynamo generated magnetic fields with strength in the range 1-100 T (similar to the
geomagnetic field).
The magnetic field of the newly born protosun was also most likely different. T Tauri stars are
young stellar objects, similar in mass to our Sun. They are in their transition between a collapsing
nebular cloud and a main-sequence star powered by hydrogen fusion (Bertout, 1989). They are
usually associated with circumstellar (protoplanetary) disks (Beckwith and Sargent, 1996), as well
as energetic outflows of gas (Edwards et al., 1993). These outflows are thought to be collimated by
large magnetic fields (Königl and Ruden, 1993).
Our Sun was once a T Tauri-like object (Feigelson, et al., 1991), thus more dynamic in its early
evolution and surrounded with stronger magnetic fields similar to T Tauri-type stars.
The presence of large magnetic fields stretching several tens of AU (Astronomical Unit) from the
source stars was confirmed in the T Tauri system through circular polarisation of the radio emission
(Ray et al., 1997). Later, the strength of the magnetic field of the T Tauri star was measured by
means of spectropolarimetry or Zeeman broadening of photospheric absorption lines in infrared
spectrum. The results indicate the surface magnetic field of T Tauri formation field stars, T Tauri
and AS 507 to be highly variable over time ranging over two orders of magnitude: 1-110 mT
(Smirnov et al., 2003 and Smirnov et al., 2004), 250 mT (Johns-Krull et al., 1999) or 100-300 mT
(Guenther et al., 1999). The high dynamics of T Tauri-type stars, non-dipole character of magnetic
fields and large angles between the rotation and magnetic axes are explanations for the observed
high variability.
These results are also similar to other T Tauri-type stars, such as TW Hyade with magnetic fields
around 250 mT (Yang et al., 2005).
Other sources of the magnetic fields in the early Solar System evolution are related to nebular
processes. Large scale lightnings in the protoplanetary nebula generated by friction of condensed
dusty particles as proposed by Desh and Cuzzi (2000) are accompanied by strong magnetic field
30
pulses, which are capable of magnetizing the condensed matter with near saturation isothermal type
remanence.
A much weaker ~ 10 T field was proposed and modeled by Desh and Mouschovias (2001),
which is a result of magnetic decoupling in a collapsing molecular cloud core extending in the
protoplanetary nebula over a region ~ 20 AU from the Sun. Such a field is nearly uniformly
distributed and could generate thermal or chemical remanence to products of early crystallization.
Thus, one would expect broad levels of magnetic fields to be recorded in extraterrestrial materials.
In the past, almost all meteorite types were subject to paleointensity studies, mainly with the
objective to detect aforementioned early nebular magnetic fields or magnetic dynamos on early
planetesimals (i.e. Butler, 1972, Brecher and Ranganayaki, 1975, Stacey, 1976, Brecher and Leung,
1979, Nagata, 1979, Sugiura et al., 1979, Funaki et al., 1981, Wasilewski, 1981 or Sugiura and
Strangway, 1983, Terho, 1996). The results, summarized for example in Acton et al. (2007) or
Sugiura and Strangway (1988), reveal paleofields mostly within the range 1-50 T. Yet, values
over 10 mT are not exceptional. This high variation is explained to be result of distinct magnetizing
events in different areas of the Solar System.
However, some of the previous studies lack explanation for several important issues, and thus
have to be considered with caution.
First issue is the timing of the magnetizing event. So far, most work done on chondrules interpret
the origin of magnetization in the early Solar System nebula, either by magnetic fields associated
with protosun, or with large scale electric discharges (lightings). This is partly supported by the
random magnetic directions of individual chondrules or clasts (magnetic conglomerate test) in some
meteorites (Sugiura et al., 1979, Funaki et al., 1981, Collinson, 1987, Morden and Collinson, 1992,
Wasilewski et al., 2002 or Kohout and Pesonen, 2005). However, it is unclear whether chondrules
are products of early nebular condensation or impact re-melting as discussed in Sears (2004).
Second, after chondrule aggregation into the parent body, ordinary and enstatite chondrites were
subject to extensive thermal metamorphism associated with various levels of metal recrystallization
and carbonaceous chondrites were affected by extensive hydrothermal alterations what may have
partly or completely erased any previous magnetic information.
Third, majority of chondrites and achondrites were exposed to numerous impact shock events,
culminating finally to the breakup of the parent body. The shock has major effects on remanent
magnetization (i.e. Kohout et al., 2008, Carporzen et al., 2005, Gattacceca et al., 2005, Kletetschka
et al., 2004b, Dickinson and Wasilewski, 2000, Pesonen et al., 1997, Morden and Collinson, 1992,
Funaki et al., 1981, Cisowski and Fuller, 1978, Wasilweski, 1977, Wasilewski, 1976, Pohl et al.,
1975). In general, without the presence of ambient magnetic fields, the shock causes partial or
31
complete demagnetization (i.e. Kletetschka et al., 2004b) while in ambient fields the occurrence of
shock generated shock remanent magnetization (SRM) occurs (i.e. Srnka et al., 1979 or IV).
However, it was shown that SRM can occur even without ambient magnetic fields at high shock
levels (Funaki and Syono, 2008) or the shock-associated heating may produce new remanent
magnetiation in meteorites (Funaki et al., 2000). The impacts and associated shock effects play a
major role in meteorite evolution as major sources of energy for thermal metamorphism as well as
for parent bodies, brecciation and final breakup.
Fourth, most of the chondrules contain magnetic minerals of multidomain sizes sensitive to
viscous decay or remangetization (either in natural or artificial magnetic fields).
Fifth, the extraterrestrial material is sensitive to alterations associated with terrestrial conditions
(i.e. Kohout et al., 2004) or with paleointensity methods which incorporate heating (i.e. Westphal,
1986).
Recently published works on ordinary chondrites partly overcome some of these difficulties by
using room temperature methods based on the efficiency ratio applied through the whole alternating
field demagnetization (AFD) sequence (Acton et al., 2007 – Fig. 10, Gattacceca and Rochette,
2004, Gattacceca et al., 2003). One of the most promising recent paleointensity work on primitive
meteorite materials is by Weiss et al. (2008) on Angrite achondrites (primitive meteorites with no
apparent shock features). The results suggest paleofields on the surface of the Angrite parent body
~ 10 T. Nevertheless, the results contain uncertainty due to the methodology based on NRM/IRM
ratios, where it was not shown whether the IRM used reached or approached saturation, and
NRM/ARM (Anhysteretic Remanent Magnetization) ratios, where the paleofield calibration is
strongly material dependent and thus of limited reliability.
Thus, the topic of meteorite paleointensity should be revised in future research. For example,
recent work by Funaki et al. (2000) analytically addressed most of the points mentioned above and
came to the conclusion that the Rumarova H5 meteorite does not preserve any primordial magnetic
record and was remagnetized by impact shock metamorphism associated with the parent body
breakup.
In the following chapters, I will outline useful techniques to analyze the magnetic record of
extraterrestrial materials.
32
Acton et al. (2007)
Acton et al. (2007)
Figure 10: Histograms of REM values and estimated paleointensities from previous studies (top)
compared with REM (middle) and REMc (bottom, REM ratio after certain cleaning AFD field)
values from Acton et al., 2006. The calculation of paleofields from REM values after a certain
cleaning field removes estimates higher than ~ 50 T, which are most likely biased by viscous or
IRM overprints. From Acton et al. (2007), modified.
5. Testing the reliability of the meteorite paleomagnetic and paleointensity data
Papers IV and V deal with the reliability of the paleomagnetic and paleointensity studies based
on the efficiency ratio (NRM/SIRM) (SIRM – Saturation Isothermal Remanent Magnetization).
This method does not incorporate any heating, and after calibration (for example Kletetschka et al.,
2004a and V (see Fig. 1 there) provides experimental calibration for various pure mineral phases of
SD (Single Domain) and MD (Multi Domain) sizes, or Yu et al., 2007 studied the grain-size
dependence of the efficiency ratio in magnetite) is able to deliver order of magnitude paleointensity
estimates if certain conditions are met. As shown in Kletetschka et al. (2004a) and V, the efficiency
ratio is dependent on mineral saturation magnetization (Ms), and thus is not suitable for mixtures of
magnetic carriers with distinct Ms. Also multiple NRM components of varying directions may result
in the distortion of the overall NRM value. These difficulties may be partially overcome by
applying techniques outlined in IV and Gattacceca and Rochette (2004).
33
In paper IV, the described REM(AF) technique is based on the efficiency determination through
the whole AFD coercivity spectra:
REM AF NRM AF SIRM AF This approach allows us to determine the efficiency ratio of various coercivity fractions (i.e. low
and high coercivity carriers) or to reveal the presence of highly isotropic (elongated) magnetic
grains.
In comparison, the approach in Gattacceca and Rochette (2004) is based on an efficiency ratio
calculated from NRM and SIRM field derivatives. Also, the methodology to determine efficiency
ratios for multiple NRM components is outlined. The advantage of this approach is lower sensitivity
to the grain-size effects described by Yu (2006) (described in more detail below). However, the
efficiency values are distorted due to the application of derivation.
There are other limiting factors of these techniques. Yu et al., 2007 (studies on magnetite bearing
basalts and gabros) and Yu (2006) (studies on commercially available synthetic magnetites)
revealed a slight grain-size dependence of the TRM (Thermal Remanent Magnetization) efficiency
ratio with double or triple enhancement in the PSD (Pseudo-Single Domain) range. Also, the
linearity of the TRM efficiency ratio during alternating field demagnetization was tested for various
magnetite grain sizes by Yu (2006). The results indicate a slight increase of the TRM efficiency
ratio as a function of the AF demagnetizing field for SD and PSD magnetite grains. Yet, the
increase in the REM value from 0 to 50 mT AF demagnetization field does not exceed a factor of
two. These results must be taken into account while interpreting the results based on efficiency ratio
techniques. However, the effects described in IV and in Gattacceca and Rochette (2004) are of
much higher amplitudes (up to order of magnitude variations in the efficiency ratio), and thus are
clearly distinguishable from the grain size effects described above.
It is important not to overestimate the capabilities or the results of the methods based on the
efficiency ratio. The efficiency ratio can provide only rough, order of magnitude, paleointensity
estimate. On the contrary, it is fast, does not require any heating (and thus does not cause any
alteration in extraterrestrial materials), and as shown in IV and in Gattacceca and Rochette (2004),
it can provide great aid in evaluating the quality of the magnetic information carried in terrestrial
and extraterrestrial materials as well as provide information about the magnetic carriers. For
example, the viscous effects, IRM-like (Isothermal Remanent Magnetization) overprints (i.e.
artificial caused by hand magnet) and low pressure shock effects affect predominantly the lowcoercivity region, while the thermal or chemical remagnetization and high pressure shock effects
influence also the high coercivity region with equal efficiency.
34
Impact cratering and related shock changes are one of the fundamental geological processes in
the Solar System. Better understanding of impact processes and their effects on magnetic properties
is essential. In IV, the results of shock experiments with the Rowley Regis diabase at ~ 1-2 GPa
pressure are described. Through REM(AF) analysis, it was shown that the shock effects in this
pressure range have similar coercivity distribution as a strong field TRM (Fig. 7 in IV).
Also described in IV, is the detection of high coercivity carriers in the Gila diabase, most likely
needle-type SD magnetites, showing an enhanced efficiency ratio in the high coercivity region (Fig.
4 in IV). Such grains have a strong magnetic anisotropy and enhanced TRM acquisition efficiency.
Thus, identification of such grains is essential when interpreting paleomagnetic and paleointensity
data.
The examples shown in IV are terrestrial samples. However, this technique is also useful while
interpreting the magnetization in extraterrestrial materials. As an example, I will now present
unpublished laboratory experiments on the effect of low pressure impact demagnetization with
chondrules from Avanhandava H4 chondrite.
6. Testing the effect of low-pressure shock demagnetization on Avanhandava
chondrules
Avahandava is a H4 fall from Brazil (Paar et al., 1976). The shock level was determined as S2
(peak shock pressure 5-10 GPa, Stöffler et al., 1991). The meteorite contains large (0.1-2.0 mm)
chondrules that have clearly delineated boundaries with the matrix (Fig. 11). This characteristic
allows us to pick up individual chondrules (oriented within 15° accuracy) and study their magnetic
properties. The rock magnetic properties of the chondrules, matrix and chondrule magnetic
conglomerate test are described in Kohout and Pesonen (2005).
Figure 11: A fragment of Avanhandava H4 meteorite used in the laboratory experiments. The size
of the fragment is 5 centimeters. The dark spherical objects are the chondrules.
35
A total of five chondrules were used in this experiment. In the first step, the chondrules were
given a SIRM with 1 T laboratory DC field and AF demagnetized (in order to test stability of the
SIRM). In the second step, the chondrules were again given a SIRM and exposed to the ~ 0.2 GPa
dynamic pressure load in the controlled low ambient magnetic field (< 500 nT, using a pair of coils
in the Helmholtz configuration). The direction of the dynamic pressure was always parallel to the
SIRM. The stability of the remanence after exposure to the dynamic pressure was again tested
through AFD.
The setup of the shock device was similar to the one described in Kletetschka et al. (2004b). The
operating principle of the device is impacting the sample (chondrule) with the free-falling mass
(aluminum, in this case). The resulting dynamic pressure estimated by the approach of Kletetschka
et al. (2004b) is ~ 0.2 GPa. The ~ 0.2 GPa dynamic pressure was the ultimate strength of the
chondrules.
The real dynamic pressure experienced by the chondrules is most likely slightly lower due to the
possible tilt of the projectile during the free-fall phase resulting in a non-planar impact on the
sample assembly. The projectile was carefully aligned before the release using the spirit level.
However, a slight tilt (~1-2°) cannot be ruled out during the free-fall phase.
To verify the ultimate strength, four chondrules were subjected to the static pressure experiments
with point contacts. The results indicate that the maximum static ultimate strength to be ~ 0.1 GPa.
Thus, dynamic pressure in the range of ~ 0.1-0.2 GPa seems to be a reasonable estimate for our
experiments.
After the completion of impact experiments, the REM(AF) method was applied on Avanhandava
chondrules to evaluate the pressure-induced changes in the distribution of the magnetization
efficiency as a function of coercivity:
REM IMP AF RM IMP AF SIRM AF where:
RMIMP(AF) is post impact remanence demagnetized with a certain AF field
SIRM(AF) is saturation remanence demagnetized with a certain AF field
The example of the REM(AF) curve of a shocked chondrule is presented in Fig. 12. Overall
magnetic remanence as the effect of the dynamic pressure load dropped by ~ 20% (initial value of
the REM(AF) curve is 0.8). A positive slope indicates the low coercivity grains being demagnetized
more progressively than the high coercivity grains. This result was consistent in all 5 chondrules.
An apparent change in slope was observed around 5 mT (Fig. 12). The two distinct slopes on the
36
REM(AF) curve (0-5 mT and 5-50 mT) may be attributed to either two distinct coercivity
populations of kamacite grains or to experimental setup related issues (i.e. shock wave reflection or
bouncing of the projectile after the impact).
1
REM
0.9
0.8
0.7
0
10
20
30
40
50
B (mT)
Figure 12: REM (AF) curve of the Avanhandava H4 chondrule subjected to impact experiment. As
the result of the impact, the overall remanence dropped by 20%. The positive slope indicates the
low coercivity grains to be demagnetized more progressively than the high coercivity grains.
7. Testing the origin of the Neuschwanstein’s NRM
While paper III deals with the low-temperature magnetic properties of the Neuschwanstein EL6
meteorite, paper VI looks in detail on its room temperature rock magnetic properties and its
paleomagnetic information. It is shown that Neuschwanstein’s bulk rock magnetic parameters
(susceptibility, hysteresis properties) are consistent with other meteorites of a similar type.
However, the interpretation of the high-temperature thermomagnetic measurements requires more
attention. As the low-temperature measurements are reported in literature in Kelvins, the
high-temperature runs are usually measured in degrees of Celsius. Thus, I will use Celsius scale in
this section.
A set of magnetic susceptibility curves as a function of temperature with a rising peak
temperature was measured upon 806°C (Fig. 4 in VI). Agico KLY-3S kappa bridge with a CS-3
temperature control unit was used. All measurements were done in argon atmosphere. As discussed
in VI, the data are consistent with the presence of 6 wt% Ni kamacite detected in the sample by
37
means of electron microscopy (Fig. 5 in VI). However, the Tc of kamacite in our measurements
(760-775°C) is higher than expected for 6 wt% Ni (740°C) which may be an indication for the
minor presence of additional Ni-poor metal (maybe due to Ni-zonation in metal) or due to the
reduction of ferrous/ferric iron to metallic iron with carbon present in the meteorite.
Another unique feature of this data set is a stepped feature with two transition temperatures
(775ºC and 645ºC) on the 806ºC Tmax cooling curve, whereas the 777ºC Tmax cooling curve does not
show any feature at 645ºC. The tentative interpretation is that the 645ºC transition corresponds to
the martensite onset temperature of 6 wt% Ni taenite. As the diffusion controlled taenite taenite
+ kamacite reaction is suppressed during 5ºC/min or faster cooling (Kaufman and Cohen, 1956), the
taenite martensite diffusionless transformation began when reaching this temperature (at 8ºC/min
cooling rate, in our case).
At the present state, a definite conclusion can not be drawn on these features and further research
is needed (for example, measurement of a similar set of high field (Ms) thermomagnetic curves to
resolve these issues).
A closer look was also taken on the paleomagnetic data. There is a clear difference in the NRM
of the samples containing fusion crust compared to those from the Neuschwanstein’s interior. While
the fusion crust samples show low and high coercivity components (Figs. 7 and 9 in VI), the
interior samples show only low coercivity (< 5 mT) during AF demagnetization (Figs. 7 and 8 in
VI). This is not surprising taking into account the MD size of kamacite in Neuschwanstein
meteorite. Due to the low stability of the Neuschwanstein’s NRM, an increased sensitivity to
remagnetization is expected and further experiments were done to evaluate this.
The REM(AF) method could not be reliably applied due to the rapid decay of the NRM during
AF demagnetization, resulting in a short segment of the REM(AF) curve (5 mT only). Thus, an
alternative approach was applied and the IRM acquisition curve was measured. The results indicate
that laboratory fields between 3 and 4 mT are sufficient to produce IRM of similar intensity as the
original NRM (Fig. 10 in VI).
As discussed further in VI, it was later discovered that all recovered Neuschwanstein meteorite
bodies were unfortunately tested by meteorite founders with a strong magnet for the presence of
iron. To evaluate the effects of the artificial magnet contamination, a similar hand magnet was
chosen and its magnetic field was mapped using a laboratory magnetometer. The fields needed to
produce an IRM comparable to Neuschwanstein’s NRM were detected up to 5 cm from the
magnet’s edge. Finally, one of the interior specimens was experimentally exposed to the magnetic
field of our hand magnet at a 5 cm distance. This resulted in the strong IRM overprint and the
38
stability of this artificially produced IRM against an alternating field is similar to the original NRM
(Fig. 11 in VI).
Thus, it is most likely that the NRM of the Neuschwanstein meteorite is of an artificial origin
produced during the meteorite handling. Use of strong hand magnets to test for the presence of iron
is common and unfortunately results in significant IRM overprints (VI, Westphal, 1986), and thus
limits the future use of the meteorites for magnetic studies. The simple and fast measurement of the
low-field magnetic susceptibility is a harmless alternative to this practice and preserves the
remanent magnetization in the meteorites.
8. Efficiency of TRM acquisition in various materials
As shown in the previous chapter, some extraterrestrial materials contain MD magnetic carriers.
Paper V deals with the sensitivity of these large MD grains to the TRM acquisition in low ambient
magnetic fields (< 1 T). This issue is of particular interest in lunar samples and meteorite
paleointensity studies as these rocks often contain metallic grains of MD size. The main conclusion
of this study is that the MD grains are not sensitive to the TRM acquisition at ambient fields below
~ 1 T. As the ambient fields decrease below this threshold, the TRM no longer follows the
empirical linear relation described in Kletetschka et al. (2004a) and begins to fluctuate around a
certain finite value (Fig. 1 in V). The behavior of the efficiency ratio is similar for all samples in the
study and the lower limit value of the efficiency ratio (reached at the threshold value of the ambient
field) seems to depend on the number of domains within the grain.
For example, hematite has relatively large domains compared to other magnetic carriers, and
thus there are only few domains within the 1 mm single crystal of hematite used in the study.
Empirical results suggest that domains within such a grain can rearrange to achieve the minimum
magnetization of 2-8% of the SIRM. Contrastingly, MD magnetite grains have smaller magnetic
domains and demagnetize down to 0.2-0.6% of the SIRM. Iron-nickel and iron grains have an even
smaller domain size (and hence more domains) and these magnetic grains can be demagnetized
down to 0.03-0.09% and 0.02-0.06% of their SIRM, respectively.
This can be a limiting factor for paleointensity studies of chondritic meteorites and some lunar
samples with abundant MD grains. Achondrites (i.e. primitive ones) and some carbonaceous
chondrites with SD magnetic grains may give more reliable results. Another promising material is
dusty olivine (olivine with dispersed kamacite particles) found in some LL3 and carbonaceous
chondrites.
39
Yu et al. (2007) conducted similar experiments with MD magnetite bearing basalts and gabbros.
According to those results, the TRM sensitivity of the MD materials continues below the ~ 1 T
threshold identified in V, and thus the materials behave similarly to SD particles (Fig. 13). It is
difficult to identify the cause of the discrepancy between the two studies. The explanation given by
Yu et al. (2007) (poor field control during the experiments in V) may not be valid as the same
procedures and experimental setup was applied to SD minerals (Kletetschka et al., 2004a and V)
where the TRM acquisition was observed well below ~ 1 T. Moreover, the experiments described
in V were repeated in a shielded room in the same facilities where the work by Yu et al. (2007) was
later done, still supporting original conclusions (V). Another possible explanation is that the
experiments in V were done on large (1 mm), single-phase, mineral crystals with its properties
typical for MD material. The magnetite grain size in the rock samples used by Yu et al. (2007) is
reported to be MD, but not specified in more detail. According to the information available there,
the rocks are the same as those described in Yu and Dunlop (2002). However, in Yu and Dunlop
(2002) it is mentioned that the rocks may contain mixtures of MD and PSD particles. Thus, they do
not need to show pure MD properties and may behave differently.
Figure 13: The comparison of the data from V and Yu et al., 2007. The discrepancy in the two data
sets may be attributed to the different nature of the samples (single crystals vs. natural minerals
embedded within rocks) used in those separate studies. The thin light-gray lines correspond to the
magnetite data published in V, while the thick dark-gray line indicates results by Yu et al. (2007).
From Yu et al. (2007).
40
9. Conclusions
The expanded database of physical properties of meteorites (I) is one of the outcomes of my
thesis and can be used in estimating the internal structure and properties of asteroids. However, the
comparison of meteorite physical properties to those of asteroids proved to be difficult due to their
scale differences (II). One option to be considered, when more data become available, is to measure
the magnetic susceptibility of asteroids and to classify them in a similar way to meteorites.
Another important finding is the temperature dependence of magnetic properties of iron bearing
sulphides (III). Daubreelite and troilite undergo several magnetic transitions at low temperatures
and may significantly contribute or even control magnetic properties of sulphide rich bodies in cold
regions of our Solar System. This important finding should be taken into account when interpreting
the interactions of such bodies with interplanetary magnetic fields. The described magnetic
behaviors of troilite and some features in daubreelite were not reported in previous literature, and
thus are fundamental.
Close attention was given to the paleointensity and paleomagnetic record in meteorites and its
reliability (IV and VI). Such information may provide constraints on ancient magnetic fields and
the evolution of minor bodies of our Solar System. The method based on the coercivity distribution
of the remanent magnetization efficiency ratio was modified and tested on various terrestrial and
extraterrestrial samples. The results show that impact related shock effects on remanent
magnetization and artificial remagnetization can be distinguished or atypical magnetic carriers can
be identified.
Furthermore, the reliability of the thermoremanent magnetization efficiency ratio as the
paleointensity tool was studied and calibrated for various minerals of different grain sizes (V). An
important discovery is the limited sensitivity of multi domain grains to thermoremanent
magnetization acquisition in low ambient fields.
The main results and implications of my thesis are:
x
Expanded database of physical properties of meteorites measured in collections and museums
using newly built mobile laboratory facility.
x
New approach in remote determination of asteroidal magnetic susceptibility. This approach may
help in matching asteroids with similar meteorites.
x
Discovery of significant low-temperature changes in magnetic properties of sulphides present in
extraterrestrial materials. This draws significant constraints on modeling the interaction of
41
minor Solar System bodies with interplanetary magnetic fields. Several new low-temperature
features are reported for the first time.
x
The REM(AF) method based on the coercivity distribution of the remanent magnetization
efficiency ratio was modified and tested on various terrestrial and extraterrestrial samples. Its
advantages were demonstrated, particularly in identifying shock features or in determination of
unusual magnetic minerals.
x
Calibration of the thermoremanent magnetization efficiency ratio for various materials and grain
sizes; discovery of limited sensitivity of multi domain grains to thermoremanent magnetization
acquisition in low ambient fields. Both have implications for the use of the efficiency ratio in
paleointensity studies.
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Appendix
Database of meteorites with their catalogue number, type, fall or find, mass, bulk density (BD),
porosity (P) and mass-normalized (KM) and volume-normalized (KV) shape-corrected (after
Osborn 1945) magnetic susceptibility values measured previously Terho (1996) and incorporated
into this thesis. The new data measured using the mobile laboratory are listed in I.
Meteorite
BISHOPSVILLE
BISHOPSVILLE
CUMBERLAND FALLS
CUMBERLAND FALLS
NORTON COUNTY
NORTON COUNTY
SHALLOWATER
JOHNSTOWN
SHALKA INTIA
SHALKA INTIA
TATAHOUINE
JONZAC
JONZAC
JONZAC
JUVINAS
PADVARNINKAI
PADVARNINKAI
PADVARNINKAI
PASAMONTE
SIOUX COUNTY
STANNERN
KAPOETA
LUOTOLAX
LUOTOLAX
LUOTOLAX
HAVERÖ
HAVERÖ
HAVERÖ
HAVERÖ
NOVO UREI
ALLENDE
ALLENDE
ALLENDE
ALLENDE
ALLENDE
COLD BOKKEVELD
FELIX
GROSNAJA
LANCE
MIGHEI
Cat. no.
HY-A1954
HY-A2310
HY-B5003
HY-B5004
GTK
HY
HY-B5109
HY
HY-A1953
HY-A1953
HY-B5117
HY-A1960
HY-A1960
HY-A1960
HY
HY-B5081
HY-B5081
HY-B5081
HY-B5083
HY
KHY
HY-B4452
HY-B7055
HY-B7055
HY-B7055
LJP
LJP
LJP
TY-9841
HY
HY-A5705
HY-A9900
HY-A9981
HY-A9981
HY-B4969
HY-A1562
HY-B5010
HY-A3646
HY-B5046
HY-A3656
Type
Aubrite
Aubrite
Aubrite
Aubrite
Aubrite
Aubrite
Aubrite
Diogenite
Diogenite
Diogenite
Diogenite
Eucrite
Eucrite
Eucrite
Eucrite
Eucrite
Eucrite
Eucrite
Eucrite
Eucrite
Eucrite
Howardite
Howardite
Howardite
Howardite
Ureilite
Ureilite
Ureilite
Ureilite
Ureilite
CV
CV
CV
CV
CV
CM
CO
CV
CO
CM
Fall / Find
FA
FA
FA
FA
FA
FA
FI
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
52
Mass
(g)
0.4
31.4
103.2
8.9
47.9
245.1
13.2
89.8
4.5
4.5
11.2
5.4
5.3
5.4
26.8
2.2
2.2
2.1
73.1
35.7
26.9
3.1
3.4
3.4
3.3
0.2
0.7
0.8
10.1
6.76
25.7
246.2
0.95
70.08
106.5
3.7
71.3
4.8
0.6
1.4
BD
(kg/m3)
3328
3104
3074
3096
2880
3050
3327
3140
2995
3209
3366
2642
2957
2946
2880
2768
2746
2795
2847
2740
2990
3095
2829
2829
2746
3290
3290
1497
3149
3300
2973
2997
2912
2965
2936
2309
2915
3195
2995
1956
P
(%)
10
18
17
17
17
17
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
575
19146
629
19521
1076
33065
1509
46726
401
7572
461
29
34
519
30
34
111
70
10
319
129
80
40
408
266
115
152
14592
13235
11808
15516
6315
336
365
245
366
397
397
3318
1008
3002
266
12222
251927
14491
860
1080
17458
780
1000
3273
2017
280
8763
3602
2880
2193
1196
12625
7526
3254
4172
480084
435421
176761
488612
208383
10001
10926
7145
10856
11647
9159
96730
32210
89911
5194
Meteorite
NOGOYA
ORGUEIL
ORGUEIL
ORGUEIL
ORGUEIL
ORNANS
ORNANS
ORNANS
SANTA CRUTZ
VIGARANO
WARRENTON
ACFER 187
KIVESVAARA
Y-793495.83
Y-793495.83
Y-793495.83
ABEE
HVITTIS
PILLISTFER
PILLISTFER
PILLISTFER
PILLISTFER
PILLISTFER
PILLISTFER
PILLISTFER
SAN CARLOS
TIESCHITZ
TIESCHITZ
TIESCHITZ
CLOVIS
FLEMING
FLEMING
GRADY
Y-791428.83
Y-791428.83
Y-791428.83
Y-791500.92
Y-791500.92
Y-791500.92
TULIA(A)
HAINAUT
BATH
BEAVER CREEK
BIELOKRYNITSCHIE
KESEN
KIFFA
MENOW
OCHANSK
QUENGGOUK
ADRIAN
Cat. no.
HY-A3657
HY
HY
HY
HY
HY
HY
HY-B5076
HY-B5105
HY-A3648
HY-B5138
MÜNSTER
LJP
NIPR
NIPR
NIPR
HY
HY
HY-A3709
HY-A3709
HY-A3709
HY-A3709
HY-A3709
HY-A3709
HY-A3709
HY-B5404
HY-A3682
HY-A3682
HY-A3682
HY
HY-B5016
HY-B5017
HY-B5020
NIPR
NIPR
NIPR
NIPR
NIPR
NIPR
HY-B5122
HY-B5025
HY
HY-A3695
HY-A3199
HY
HY-B5040
HY-A3696
HY-A3679
HY-A3674
HY-B4967
Type
CM
CI
CI
CI
CI
CO
CO
CO
CM
CV
CO
CR
CM
CR
CR
CR
E4
E6
E6
E6
E6
E6
E6
E6
E6
H
H3
H3
H3
H3
H3
H3
H3
H3
H3
H3
H3
H3
H3
H3-4
H3-6
H4
H4
H4
H4
H4
H4
H4
H4
H4
Fall / Find
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FI
FI
FI
FI
FI
FA
FA
FA
FA
FA
FA
FA
FA
FA
FI
FA
FA
FA
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FA
FA
FA
FA
FA
FA
FA
FA
FA
FI
53
Mass
(g)
0.4
3.6
0.7
5.8
1.5
3.8
4.9
4.8
0.7
56
59.7
1.46
1.2
0.21
0.21
0.21
18.2
21.7
9.2
1.8
2.2
1.8
1.8
8.3
8.4
2.5
12.3
11.7
11.6
76.9
210.1
12.6
6.6
2.86
2.86
2.86
0.67
0.67
0.67
10.7
8.9
92.5
11.4
29
114.7
0.9
45.8
8.9
1.5
13.4
BD
(kg/m3)
1996
2250
2250
2250
2250
3450
3450
2662
1792
3211
2785
3223
2396
3099
3099
3099
3710
3610
3630
3595
3662
3648
3595
3604
3647
3460
3206
3338
3310
3280
3376
3495
3430
3569
3569
3242
3327
3327
3327
3446
3554
3460
3162
3447
3510
2898
3069
3317
2995
3192
P
(%)
26
26
26
26
11
11
11
4
4
4
9
9
9
6
8
13
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
133
2661
5993
134833
592
6378
2868
1831
1818
688
2680
3018
12784
410
15287
14283
13729
39871
39156
63697
55809
79207
57278
59788
57165
62105
12078
11646
11879
11734
4450
6158
9901
14780
8737
8790
10382
23762
24468
18247
9041
30223
5310
22286
29994
24298
25259
30688
22205
29135
6754
13325
143505
98963
63183
48391
12328
86063
84045
412020
9814
473735
442618
425461
1479206
1413520
2312190
2006316
2900574
2089518
2149372
2060217
2264987
417892
373355
396526
388398
145954
207897
346038
506951
311811
313710
336589
790570
814060
607079
311553
1074114
183720
704695
1033881
852869
731993
941814
736541
872599
215581
Meteorite
GRUVER
HAT CREEK
METSÄKYLÄ
METSÄKYLÄ
METSÄKYLÄ
METSÄKYLÄ
METSÄKYLÄ
ORIMATTILA
ORIMATTILA
RANSOM
SELMA
SENECA
SERES
UTE CREEK
ACFER 048
ACFER 061
ACFER 065
ACME
AGEN
ALLEGAN
ALLEGAN
ALLEGAN
AMBAPUR NAGLA
BARBOTAN
BEARDSLEY
CANGAS DE ONIS
COLLESCIPOLI
FOREST CITY
HESSLE
JILIN
LABOREL
MISSHOF
MOORESFORT
NAMMIANTHAL
NUEVO MERCURIO
PULTUSK
PULTUSK
PULTUSK
STÄLLDALEN
STÄLLDALEN
TABOR
ACFER 024
ACFER 024
ACFER 024
ACFER 025
ACFER 025
ACFER 025
ACFER 025
ACFER 025
ACFER 025
Cat. no.
HY-B5023
HY-B5028
GT
HY
HY-B5064
HY-B7288
HY-B7288
HY-B5075
TY-?
HY-B5096
HY-B5107
HY-B5108
HY-A3641
HY-B5123
Münster
MÜNSTER
MÜNSTER
HY-B4966
HY-A3194
HY-A3691
HY-A3692
HY-A3693
HY-A3694
HY-A3626
HY-A1905
HY-A3627
HY-B5000
KHY
KHY
HY-B5041
HY-A3208
HY-A3670
HY-A3635
HY-A3672
HY-B1984
784
HY-A3638
HY-B5095
KHY
KHY
HY-A3678
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
Type
H4
H4
H4
H4
H4
H4
H4
H4
H4
H4
H4
H4
H4
H4
H4-5
H4-5
H4-5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
Mass
Fall / Find
(g)
FI
4.5
FI
26.8
FI
203.1
FI
31.5
FI
12.3
FI
5.71
FI
207.41
FI
42.8
FI
3.5
FI
79.7
FI
2.9
FI
20
FI
1.3
FI
8.7
FI
2.46
FI
1.39
FI
1.9
FI
42.5
FA
38.3
FA
15
FA
39.7
FA
15
FA
3
FA
10
FA
11.5
FA
1.9
FA
108
FA
149.3
FA
127.8
FA
59
FA
28.8
FA
4.2
FA
4.6
FA
29.8
FA
52.4
FA
43
FA
183.1
FA
21
FA
37.3
FA
142.2
FA
14.6
FI
4.61
FI
4.61
FI
4.61
FI
2.72
FI
2.72
FI
2.72
FI
1.72
FI
1.72
FI
1.72
54
BD
(kg/m3)
3456
3521
3210
3310
3284
3237
3292
3534
3420
3568
3373
3289
3244
3340
3549
3599
3496
3309
3384
3031
3070
3056
2722
3362
3479
3794
3456
3440
3270
3489
3332
3226
3280
3419
3059
3469
3510
3495
3540
3600
3470
3505
3505
3505
3719
3719
3719
3302
3302
3302
P
(%)
3
2
2
3
5
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
12133
419322
23650
832727
5547
4012
3554
5372
14282
15748
20380
5427
8852
33981
5533
9992
26507
16026
4143
183601
131770
115036
176836
504724
538588
727166
183057
291150
1102338
184803
354606
953984
560262
137091
24623
21894
21871
21933
20897
21132
21892
22026
20807
17328
30132
1585
30503
27031
15548
30753
29470
24310
19804
45053
31182
10333
12888
11802
11975
11465
11838
14619
21101
20096
23690
746325
672149
668364
597017
702558
735171
830586
761204
715765
566610
1051297
52804
984033
886628
531573
940723
1022312
853295
692148
1594887
1122560
358548
451735
413672
419711
426400
440259
543666
696748
663576
782239
11
16
2
10
7
7
7
3
3
3
4
4
4
4
4
4
Meteorite
ACFER 046
ACFER 046
ACFER 046
ACFER 067
ACFER 073
ACFER 073
ACFER 073
ACFER 073
ACFER 073
ACFER 073
ACFER 098
ACFER 098
ACFER 098
ACFER 275
ACFER 308
ALAMOGORDO
CASTALIA
COLBY (KANSAS)
COLDWATER (STONE)
COPE
COVERT
FARLEY
FERGUSON SWITCH
FERGUSON SWITCH
GILGOIN
HOWE
HUGOTON
CHAMBERLIN
MARSLAND
PLAINVIEW (1917)
PLAINVIEW (1917)
SALINE
SALINE
TEXLINE
TIMOCHIN
TRAVIS COUNTY
UBERABA
WELLMAN (A)
ACFER 275
STONINGTON
DJATI-PENGILON
CHARSONVILLE
KERNOUVE
LANCON
MOUNT BROWNE
NANJEMOY
TRENZANO
VERNON COUNTY
CAPE GIRARDEAU
COBIJA
Cat. no.
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
MÜNSTER
HY-A1910
HY-A3628
HY-B4997
HY-B4999
HY-B5001
HY-B5002
HY-B5009
HY-B5013
HY-B5014
HY-A3706
HY-B5031
HY
HY
HY-B5055
HY-A1904
HY-A1912
HY-A3697
HY-A3698
HY-B5118
HY-A3683
HY-B5119
HY-A3689
HY-B5141
Münster
HY-B5114
HY-A3700
HY-A3629
HY-A3708
HY-A2451
HY-A3671
HY-A3673
HY-A3684
HY
HY-A3663
HY-A3647
Type
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5
H5-6
H5-6
H6
H6
H6
H6
H6
H6
H6
H6
H6
H6
Fall / Find
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FA
FA
FA
FA
FA
FA
FA
FA
FI
FI
55
Mass
(g)
4.51
4.51
4.51
1.44
2.25
2.25
2.25
1.33
1.33
1.33
4.03
4.03
4.03
1.8
2.05
81.3
55.2
11.3
3.6
50.4
34.4
131.8
44
28.7
0.4
27.6
75.8
104.4
2
281.7
401
94.5
34.2
15.7
18.3
13
5.8
16.3
1.8
29.1
3.7
10.6
5.8
10.5
25.4
28.4
17.4
25.8
6.8
25.5
BD
(kg/m3)
3163
3163
3163
3448
2955
2955
2955
3319
3319
3319
3087
3087
3087
2564
3639
3474
3415
3358
3594
3456
3302
3331
3405
3460
3994
3356
3300
3340
3385
3543
3541
3533
3495
3562
3245
3415
3386
3537
3564
3394
3694
3414
3555
3382
3381
3376
3152
3180
3173
3431
P
(%)
1
1
1
5
1
1
1
3
3
3
9
9
9
1
1
2
2
1
8
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
4034
127605
4027
127372
3988
126129
9759
336501
3305
97652
4159
122893
4060
119980
4953
164402
6182
205165
6062
201211
12802
395191
12815
395613
13114
404844
16260
416901
25142
914907
13504
469119
13941
476079
7132
239477
8068
289959
7556
261129
2404
79394
4069
135541
10867
370033
8593
297316
18952
756944
10320
346336
3863
127470
4210
140623
18692
632731
13172
466674
24383
19510
19712
6210
12412
19976
20326
11698
12611
17955
45242
40790
29448
28480
32633
26791
42095
25163
13377
861439
681872
702125
201527
423863
676373
718914
416901
428028
663260
1544548
1450101
995925
962910
1101701
844459
1338633
798434
458951
Meteorite
GLADSTONE (STONE)
MILLS
MORLAND
MORLAND
OVID
PIPE CREEK
REXLEBEN
WILOT
KISVARSANY
LINUM
MEZO-MADARAS
CYNTHIANA
LANZENKIRSCHEN
TENNASILM
TENNASILM
BARRATTA
BARRATTA
BARRATTA
DALGETY DOWNS
GOODLAND
GRASSLAND
KRAMER CREEK
MC KINNEY
MC KINNEY
MC KINNEY
VERA
AUSSON
ERGHEO
FARMINGTON
FARMINGTON
KNYAHINYA
SEVRUKOVO
ARRIBA
ARRIBA
ARRIBA
BEAVER
BEENHAM
BLUFF
CHANDAKAPUR
LA LANDE
ROY (1933)
TAIBAN
ALEPPO
ALFIANELLO
ALFIANELLO
ALFIANELLO
ALFIANELLO
ALFIANELLO
BORI
BRUDERHEIM
Cat. no.
HY-B5018
HY-B4383
HY
HY-B5068
HY-B5080
HY-A3710
HY-A3705
HY-B5142
HY-B5042
HY-B5049
HY-A3633
HY-A3630
HY-B5048
HY-A3651
HY-A3681
HY
HY-A3645
HY-A3645
HY-A4860
HY-B5019
HY-B5022
TY-9842
HY-A1559
HY-B5056
HY-B5057
HY-B5137
HY-A3659
HY
HY-A1556
HY-A1556
HY-A3632
HY-A3652
HY-A3518
HY-B4972
HY-B4973
HY-B1985
HY-A1909
HY
HY-A3201
HY-B5045
HY-B5097
HY-B5116
HY-A2446
HY-3195
HY-A3195
HY-A3196
HY-A3197
HY-A3214
HY-A3200
KHY
Type
H6
H6
H6
H6
H6
H6
H6
H6
L
L
L3
L4
L4
L4
L4
L4
L4
L4
L4
L4
L4
L4
L4
L4
L4
L4
L5
L5
L5
L5
L5
L5
L5
L5
L5
L5
L5
L5
L5
L5
L5
L5
L6
L6
L6
L6
L6
L6
L6
L6
Mass
Fall / Find
(g)
FI
63.5
FI
7.8
FI
105
FI
92.2
FI
29.4
FI
2.2
FI
10.3
FI
8.4
FA
24.4
FA
24
FA
20.3
FA
5.4
FA
18.9
FA
694.7
FA
3.1
FI
263
FI
1.86
FI
262.82
FI
148.9
FI
7
FI
2.8
FI
21.2
FI
203.2
FI
68.2
FI
11.2
FI
2.8
FA
26.1
FA
55
FA
9.01
FA
176.05
FA
7.2
FA
19.3
FI
41.4
FI
212.6
FI
30.6
FI
82.4
FI
68.4
FI
42.4
FI
7.1
FI
76.3
FI
9.7
FI
48.6
FA
0.5
FA
50.9
FA
50.7
FA
139.3
FA
60.2
FA
6.9
FA
0.5
FA
78.8
56
BD
(kg/m3)
3433
3205
3550
3563
3401
3486
3546
2995
3248
3251
3269
3135
3494
3310
3095
3450
3437
3451
3429
3512
3084
3205
3500
3492
3528
3327
3217
3310
3384
3411
3374
3497
3357
3372
3320
3461
3341
3390
3219
3426
3296
3473
2496
3260
3248
3277
3248
3280
4992
3360
P
(%)
1
0
0
0
6
1
2
2
7
7
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
8994
308750
5603
179577
20949
743707
23573
839901
7463
253814
39300
1370010
33874
1201169
7151
214182
7700
250085
6349
206405
4985
162953
2688
84277
11923
416589
7181
237691
6853
212105
8677
299364
9334
320826
8958
309153
5227
179240
8727
306500
1431
44142
1450
46482
7769
271928
7959
277927
7330
258619
5475
182169
9480
304963
7981
264166
7137
241526
8860
302229
6351
214298
10445
365254
5798
194647
4386
147908
5535
183767
5049
174762
5952
198866
7996
271067
7281
234387
3722
127502
1617
53280
6071
210855
8054
262574
7602
8265
7176
8099
8388
249117
268445
235370
404318
281843
Meteorite
BUSCHHOF
CABEZO DE MAYO
DANVILLE
DURALA
FUTTEHPUR
GIRGENTI
GROSSLIEBENTHAL
HOLBROOK
HOLBROOK
CHANTONNAY
JACKALSFONTEIN
JACKALSFONTEIN
KYUSHU
LE PRESSOIR
LISSA
LUNDSGARD
MARION
MARION
MAUERKIRCHEN
MILENA
MOCS
MOCS
MONZE
NERFT
NEW CONCORD
NEW CONCORD
OESEL
ORVINIO
OVAMBO
PACULA
ST. MICHEL
TENHAM
TOURINNES-DE-LA-GROSSE
ZEMAITKIEMIS
BATH FURNACE
BREWSTER
CALLIHAM
DE NOVA
ELLA ISLAND
HAMILTON
HARRISONVILLE
CHATEAU RENARD
KERMICHEL
LADDER CREEK
L'AIGLE
LAKETON
LONG ISLAND
NASHVILLE
NEENACH
NESS COUNTY
Cat. no.
HY
HY-B4989
HY-A3631
HY-A3206
HY-A2449
HY-A2450
HY-A1550
928/130795
KTK
HY-B4996
HY-B5037
HY-B5038
HY-A2454
HY-A3669
HY-A2452
HY-A2453
HY-A2455
HY-A2456
HY-A2457
HY-A2458
82/0167
HY-A2459
HY-B5067
HY-A3211
HY-A1566
HY-A1566
HY-A2463
HY-A3644
HY-B5079
HY-A2461
HY
HY-A5730
HY-A2464
HY-B5143
HY-A3198
HY-B4986
HY-B4990
HY-B5007
HY-B5008
HY-B5026
HY-B5027
HY-A3203
HY-A3707
HY-B5043
HY-A3207
HY-B5044
HY-A3209
HY-B4385
HY-B1983
HY-A3636
Type
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
Mass
Fall / Find
(g)
FA
35.8
FA
11.9
FA
12
FA
28.6
FA
2
FA
5.6
FA
177.3
FA
33.3
FA
40
FA
62.6
FA
6.2
FA
1.5
FA
22.3
FA
1.1
FA
0.8
FA
29.2
FA
45.5
FA
4.4
FA
28.6
FA
92.2
FA
146.3
FA
349.2
FA
27
FA
5.3
FA
3.3
FA
386.25
FA
24
FA
2.5
FA
39.7
FA
22.8
FA
20.4
FA
22.4
FA
5
FA
9.6
FI
26.9
FI
6.1
FI
2.6
FI
5.6
FI
29.8
FI
186.1
FI
40.8
FI
7.5
FI
5.7
FI
41.1
FI
29.2
FI
97.5
FI
26.9
FI
40.9
FI
27.5
FI
684.6
57
BD
(kg/m3)
3220
3235
3404
3234
3566
3289
3257
3220
3170
3572
3438
2825
3260
2968
2420
3286
3245
3379
3245
3264
3311
3287
3319
3307
3395
3337
3190
3120
3339
3261
3390
3363
3327
3549
3357
3441
3556
3289
3199
3373
3417
3435
3347
3331
3367
3333
3315
3423
3402
3368
P
(%)
9
9
6
6
3
1
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
6684
215230
9283
300320
8653
294561
8296
268293
31673
1129468
11284
371126
4042
131659
4708
151605
4989
158147
20030
715464
9109
313152
5080
143497
8781
286262
116322
3452447
8517
206110
9582
314864
5107
165734
16290
550454
7102
230445
7933
258929
7951
263259
7109
233662
9520
315979
11235
371551
8956
304044
10479
349687
5971
190478
9683
302124
8637
288402
7379
240626
6302
213647
6192
208238
7727
257067
7115
252500
7098
238288
1885
64865
2286
81273
4450
146351
5878
188032
7622
257076
4807
164247
10726
368425
1152
38572
1776
59167
7179
241706
3967
132205
1518
50324
6623
226719
5588
190089
2024
68185
Meteorite
NORCATEUR
OTIS
POTTER
POTTER
RUSH CREEK
SALLA
SALLA
SMITH CENTER
SPRINGFIELD
TRYON
VALKEALA
VARPAISJARVI
VOUILLÉ
WACONDA
ZAVID
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
Cat. no.
HY-B5069
HYHY-B5090
HY-B5092
HY-B5098
GT
HY
HY-B5112
HY-B5113
HY-B5120
HY
HY-B5136
HY-A3212
HY-A3687
HY-A3213
HY
HY
HY
HY
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
Type
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L6
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
Fall / Find
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FI
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
58
Mass
(g)
19.7
7.3
46.6
76.2
223.1
462.1
95.2
10.1
25.1
36
135.6
2.8
40.1
27.5
178
106.3
125.4
122.4
127.2
80.2
79.5
77.5
11.9
11.9
11.6
19.5
19.4
18.7
19.4
19.3
18.6
26.5
26.3
25.5
29.4
29.1
28.1
27.3
27.1
26.1
4.6
4.6
4.4
55.1
54.6
52.9
38
37.8
36.3
43.1
BD
(kg/m3)
3262
3343
3300
3214
3437
3390
3390
3465
3288
3359
3340
3368
3381
3260
3309
2850
2910
2940
2920
3030
3019
3048
3114
3125
3093
3041
3073
3169
3025
3010
3084
3005
3017
2996
3025
3051
3095
3027
3039
3001
2906
2953
3082
3011
3014
3000
2998
3018
3034
3073
P
(%)
4
17
17
17
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
2188
71377
1556
52029
1224
40393
803
25820
6847
235326
3772
2839
4556
1488
2928
8485
11401
4885
10215
3251
3194
4191
127883
98383
149785
49984
97793
285769
385477
159242
337999
92649
92941
123207
4266
4240
4375
3859
3882
3969
4612
4051
5264
3882
3711
4052
3421
3323
3613
3632
3487
4102
3318
5001
4149
1795
2413
2360
3087
2730
2998
3447
3930
3978
2960
129271
128013
133350
120155
121310
122768
140257
124493
166832
117424
111702
124958
102815
100247
108233
109853
106401
126944
100430
151988
124519
52165
71270
72747
92953
82293
89942
103333
118611
120702
90968
Meteorite
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
BJURBÖLE
PARNALLEE
Y-790448.104
Y-790448.104
Y-790448.104
SOKO-BANJA
SOKO-BANJA
ALTA'AMEEM
GUIDDER
NYIRABRANY
PARAGOULD
Cat. no.
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
HY(13)
KHY
KHY
QHY
TKK-4606
TKK-9815.1
TKK-9815.2
TKK-9815.3
TY-9840
HY-A3637
NIPR
NIPR
NIPR
HY
HY
HY-B4670
HY-B2024
HY-B5072
HY-B5082
Type
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
L/LL4
LL3
LL3
LL3
LL3
LL4
LL4
LL5
LL5
LL5
LL5
Fall / Find
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FI
FI
FI
FA
FA
FA
FA
FA
FA
59
Mass
(g)
42.7
41.5
25.3
25.1
24.2
28.4
28.4
27.4
56.4
56.2
55.8
67.7
67.6
65.2
12.5
12.5
12
7.4
7.4
7.2
5.7
5.7
5.5
10
10
9.6
36.8
36.5
35.5
37.2
37.1
35.9
48.2
128.2
91.4
944.1
53.7
48.2
44.5
72.6
184.7
2.42
2.42
2.42
2.42
2.78
10.6
5.3
21.4
5.7
BD
(kg/m3)
3045
3016
2971
2983
2971
3073
3050
3110
3017
3017
3012
3057
3066
3153
3068
3046
3070
3077
3077
3124
2993
3116
3092
3094
3037
3115
3066
3059
3042
3016
3035
3054
2880
2890
2910
3010
2910
2860
2850
3016
3243
3178
3178
3178
3450
3450
3206
3227
3188
3407
P
(%)
16
16
16
17
17
17
17
17
17
14
14
14
16
16
16
17
17
17
3
3
3
3
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
3689
112322
3528
106401
3001
89162
2829
84381
3149
93568
4033
123921
4003
122088
4033
125425
2974
89723
3369
101638
3294
99207
3659
111851
4106
125899
3881
122364
2377
72934
2213
67422
2192
67297
4675
143860
4949
152281
4596
143573
3282
98245
3537
110228
3968
122706
3713
114884
4155
126197
4224
131584
4260
130604
3996
122237
3349
101880
3271
98640
3218
97667
3022
92284
3468
99878
4080
117908
3744
108943
4114
123831
3239
94253
4432
126742
3513
100114
3697
111506
3064
99367
1142
36292
1219
38755
1430
45439
1819
62756
1299
44820
1866
59832
515
16615
1570
50058
3529
120232
Meteorite
TUXTUAC
Y-8410.64
Y-8410.64
Y-8410.64
DHURMSALA
DHURMSALA
ENSISHEIM
ENSISHEIM
ENSISHEIM
JELICA
MANBHOOM
MANBHOOM
VAVILOVKA
ARCADIA
BOELUS
LAKE LABYRINTH
OUBARI
CHASSIGNY
CHASSIGNY
CHASSIGNY
NAKHLA
ZAGAMI
ZAGAMI
ZAGAMI
ZAGAMI
ZAGAMI
ZAGAMI
EETA 79001.138
EETA 79001.138
EETA 79001.138
Cat. no.
HY-B4382
NIPR
NIPR
NIPR
HY
HY
HY-A3701
HY-A3701
HY-A3701
HY-A1957
HY-A1958
HY-A1958
HY-A1960
HY-B4971
HY-B4983
HY-A2282
HY-B5078
HY-A1956
HY-A1956
HY-A1956
HY-D49
HY-B6975
HY-B6975
HY-B6975
HY-B6975
HY-B6975
HY-B6975
LPI
LPI
LPI
Type
Fall / Find
LL5
FI
LL5
FI
LL5
FI
LL5
FI
LL6
FA
LL6
FA
LL6
FA
LL6
FA
LL6
FA
LL6
FA
LL6
FA
LL6
FA
LL6
FA
LL6
FI
LL6
FI
LL6
FI
LL6
FI
Chassignite
FA
Chassignite
FA
Chassignite
FA
Nakhlite
FA
Shergottite
FA
Shergottite
FA
Shergottite
FA
Shergottite
FA
Shergottite
FA
Shergottite
FA
Shergottite
FI
Shergottite
FI
Shergottite
FI
60
Mass
(g)
1.3
3.14
3.14
3.14
55.1
75.2
4.52
4.5
4.5
12.5
1.17
1.2
16.8
40.5
20.8
402.6
41.8
0.4
0.378
0.087
6.525
41.2
2.96
2.96
2.96
41.1
40.4
2.45
2.45
2.45
BD
(kg/m3)
3244
3370
3370
3370
3330
3290
3450
3304
3210
3058
3450
2993
3104
3191
3245
3285
3189
2496
3319
3287
3230
3086
3071
3071
3071
3083
3043
3124
3124
3124
P
(%)
2
2
2
6
7
7
7
8
8
8
KM (Osb) KV (Osb)
(10-8 m3/kg) (10-6 SI)
1283
41613
5014
168988
5050
170192
4719
159042
1596
53144
1581
52010
6802
234686
5792
191382
6634
212959
281
8589
240
8296
736
22019
378
11718
368
11730
774
25116
1383
45446
1080
34445
9
220
14
480
45372
1491370
179
5791
70
2173
67
2060
36
1100
18
550
67
2062
73
2210
65
2040
64
2000
60
1890